Category Geology

How long does it take the International Space Station to orbit the Earth ______ minutes?

The International Space Station (ISS) is a large spacecraft that orbitis around Earth every 90 minutes. It is not only a science laboratory but also serves as a home to crews of astronauts and Cosmonauts.

Its laboratory has components from the United States, Russia, Japan, and Europe.

The space station is used by National Aeronautics and Space Administration (NASA) scientists to learn more about living and working in space. The research here will make it possible to send humans farther into space than ever before.

History                                                                                               

Originally called ‘Freedom’ in the 1980s, then U.S. President Ronald Reagan authorised NASA to build the space station. It was redesigned in the 1990s to reduce costs and expand international involvement, at which time it was renamed.

In 1993, the U.S. and Russia agreed to merge their separate space station plans into a single facility and incorporate contributions from the European Space Agency (ESA) and Japan.

It took 10 years and more than 30 missions to assemble the space station. It was launched in 1998 with the help of the U.S., Russia, Canada, Japan, and the participating countries of the ESA. The first piece of the ISS was launched in November 1998. The ISS is the size of a large five-bedroom house or a football field and is able to support a crew of six people and some visitors

It is made up of several parts that were assembled in space by astronauts. The first crew reached the space station on November 2, 2000. People have lived on the space station ever since.

International Space Station

The space station is equal to a five-bedroom house or the size of a football field and is able to support a crew of six people, plus visitors. The laboratories in the space station help the crew members to do research that could not be done anywhere else.

At the ISS, the scientists also study what happens to the human body when people live in microgravity (place where there is almost no gravity) for a long time.

The space station has solar arrays, which collect energy from the sun to provide electrical power. The arrays are connected to the station with a long truss, which is a beam that is the backbone of the space station.

There are radiators on the truss that control the space station’s temperature. Astronauts reach the space station on the Russian Soyuz spacecraft Operating the space station is more complicated than other space flight programmes as it is an international programme. Each partner is mainly responsible for managing and running the hardware it provides It is the largest space station ever constructed and yet it continues to be assembled in orbit.

Till now, it has been visited by astronauts from 18 countries During Prime Minister Narendra Modi’s recent visit to the U.S.. President Joe Biden said that India and the US. will collaborate to send an Indian astronaut to the ISS in 2024.

Picture Credit: Google

Did the Milky Way shape-shift?

Embark on a journey to Verona and meet the dedicated volunteers preserving the legacy of one of Shakespeares greatest heroines

The House of Juliet also known as Casa di Gillette” is Italian, is more than just an old building in Verona Italy It is believed to have once belonged to the Cappello family which according to the legend inspired the famous Capulet family in English playwright William Shakespeare’s play Romen & haliet This is the very house where Gulietta Capuleti the supposed inspiration behind, the tragic heroine of Shakespeares play, is said to have livest

A global love connection

But the House of Juliet is not just a tounst attraction it is a hub of heartwarming connections from around the world Thousands of people lene letters addressed to Juliet. expressing their deepest feelings about love, relationship and life when they visit this medieval 13th Century palace Some letters are placest in a postbox at the house itself. while others are simply addressed to Juliet, Italy and sent from all corners of the globe

Juliet Club

The Juliet Club, a hidden gem tucked away in the backstreets of Verona since 1972 is a place where the timeless spirit of romance thrives. The dubs heart and soul lie in the dedicated committer of a dozen local women who affectionately call themselves The Secretaries of Juliet These volunteers take on the heartwanning task of responding to the staggering 50.000 letters Juliet receives annually. They diligently strive to answer every letter, even those written in languages beyond Italian or English, seeking local speakers to help bridge the communication gap. Stepping into the workroom fillest with boxes of handwritten letters, the secretaries embark on their mission to provide solace, wisdom, and advice on matters of the heart

This unique experience is not just limited to the dedicated team: anyone can be a part of Juliets legacy A visitor can drop in for a day and become Juliet’s secretary reading and responding to letters that resonate with their hearts. Each response is penned on official Club di Giulietta stationery and signed off as Secretary of Juliet.”

The first secretary of Juliet

The tradition of answering Juliet’s letters has a history dating back to the 1930s when the guardian of Juliets grave in Verona, Ettore Solimani, first began replying to letters left for the literary character. Handwritten letters have retained their allure, despite the prevalence of modem communication methods. The clubs archive stands as a treasure trove of countless love stories and a testament to the enduring power of love expressed through pen and paper

The Juliet Club and its Secretaries carry forward the legacy of Shakespeare’s iconic character, extending love hope, and empathy to countless hearts seeking solace and connection.

 

Did the Milky Way shape-shift?

For the longest time, astronomers have been trying to unlock the mystery surrounding our Milky Way galaxy. Astronomers have known that our galaxy looks like a spiral ever since the 1950s. Galaxies are classified based on their shapes and physical features. activity in their central regions, and so on. The presence of spiral anns in our galaxy has placed it in the category of spiral galaxies

What are spiral galaxies?

Galaxies are generally categorised as spiral (like our Milky Way). elliptical and irregular. Spiral galaxies have winding spiral arms. It makes them look like pinwheels and the cosmic entities comprise stars, gas, and dust.

Their spiral arms are composed of gas and dust from which bright younger stars are born. Stars are actively being formed in the spiral galaxies. The younger stars are formed in the arms that are rich with gas while the older stars occur in the halo, in the disk and within the bulge. And this is happening in our neighbouring galaxies as well The spiral galaxies are further grouped into normal spirals and barred spirals. A barred spiral galaxy has ribbons of stars, gas, and dust running across their centres. Our galaxy as well as Andromeda galaxy belong to the subtype of a barred spiral galaxy But here is a new spin on the story. New observations have shown that our galaxy was not always a spiral Reporting in the scientific journal Monthly Notices of the Royal Astronomical Society, astronomer Alister Graham observed that galaxies evolve from one shape to another. He used old and new observations to show how the evolution of galaxies from one shape to another takes place. This process is called galactic speciation. The clashes and subsequent mergers with other galades result in the process of cosmic evolution.

So our galaxy transformed from a dust-poor lenticular galway to the spiral galaxy we know it as today. In future, between 4 billion and 6 billion years, our galaxy is all poised to merge with its neighbouring galaxy, the Andromeda galaxy Following this collision and merger, the daughter galaxy resulted will be a dust rich lenticular galaxy, with an intact disk but without the spiral structure.

Picture Credit: Google

Does Saturn have a storm spot?

The Great Red Spot is the largest storm in our solar system. An anticyclone that is over 16,000 km wide-large enough to engulf the entire Earth-the Great Red Spot has been on Jupiter’s surface for hundreds of years.

A new study has shown that Satum Jupiters neighbour, also has long-lasting megastorms. While these are less colourful and blander than those on Jupiter, they do have impacts deep in Saturn’s atmosphere that remain for centuries. The study was published on August 11 in the journal Science Advances

Similar to hurricanes

Similar to hurricanes on Earth but much much larger, megastorms on Satum occur every 20 to 30 years. The causes for these megastorms in Saturn’s atmosphere. which is made up mainly of hydrogen and helium along with traces of methane ammonia and water, remains unknown. Based on radio emissions from Satum. astronomers from the University of California, Berkeley, and the University of Michigan, Ann Arbor, noticed anomalies in the concentration of ammonia gas in the atmosphere. While the concentration of ammonia at mid-altitudes is lower, it was enriched at lower altitudes. 100 to 200 km deeper in the atmosphere.

Precipitation and re-evaporation

The researchers were able to connect this to the past occurrences of megastorms in Satum’s northern hemisphere. According to them, ammonia is being transported from the upper to the lower atmosphere. This effect, which they believe can last for hundreds of years, occurs through the processes of precipitation and re-evaporation.

Additionally, this study reveals that Saturn and Jupiter are very dissimilar despite the fact that both gas giants are made of hydrogen gas. The tropospheric anomalies in Jupiter have been connected to its zones (whitish bands) and belts (darkish bands), while those on Saturn are caused by cyclones.

These differences between Saturn and Jupiter challenge scientists on what they know about the formation of megastorms on gas giants and other planets. Understanding this would not only further our knowledge of terrestrial meteorology, but may also inform us as to how they are formed and studied on exoplanets in the future.

Picture Credit: Google

How stars like the Sun generate energy through nuclear fusion?

Stars like our Sun radiate huge quantities of energy because of the nuclear fusion reaction taking place inside their core. Can we use the same idea to generate power that is clean and cheap? Where are scientists around the world working on such projects.

The energy scenario in the world is changing as natural sources conventionally used for generating energy like fossil fuels, oil and coal are fast depleting.

But there are abundant energy sources that cause minimal climate change. Nuclear energy is one such option being used worldwide. In this process, energy is released from the nucleus of an atom either by splitting the heavy atom into two (nuclear fission) or by combining two light atoms into a heavier one (nuclear fusion).

For more than 50 years, energy has been generated in nuclear power plants through fission, a process in which heavy elements such as uranium are bombarded by neutrons, resulting in the splitting of the nuclei and the release of huge amounts of energy in the form of heat.

Nuclear fusion is the opposite process. In fusion reactors, light atomic nuclei are compressed under intense pressure and heat, forcing them to combine together to form heavier nuclei. Fusion also results in the release of huge quantities of energy.

Special conditions Normally, atomic nuclei repel each other if we try to bring them closer; to force them to come close and ultimately fuse together, special conditions have to be generated in the form of very high pressure and extremely high temperatures.

Stars like our Sun radiate huge quantities of energy because of the nuclear fusion reaction taking place inside their core- hydrogen is continuously changing to helium.

The core experiences extremely high pressure because of the gravitational force exerted by the mass of the gigantic star itself, this pressure also leads to the generation of very high temperature inside the star. So, the basic requirement for a fusion reaction is to create a star-like situation inside the reactor in terms of temperature and pressure. To generate such conditions, a lot of energy is needed.

The process must be optimised to generate more energy than it consumes. Fusion could be utilised to generate electricity commercially. The main fuels used in nuclear fusion are deuterium and tritium, both heavy isotopes of hydrogen. Deuterium constitutes a tiny fraction of natural hydrogen, only 0.0153 per cent, and can be extracted inexpensively from seawater. The amount of deuterium present in one litre of water can in theory produce as much energy as the combustion of 300 litres of oil! This means that there is enough deuterium in the oceans to meet human energy needs for millions of years.

Building a fusion power plant that can withstand the immense temperature and pressures produced by this process is one of the century’s greatest engineering challenges. The fuel must be heated to about 100 million degrees Celsius. At that hotter-than-the-sun temperature, a fully ionised gas-plasma is formed. The plasma will then be ignited to create fusion.

Picture Credit: Google

What powers a spacecraft?

Scientists send spacecraft to probe objects in space. These spacecraft carry instruments that help them take pictures and collect data in space and send them back to Earth. But to do this, the spacecraft needs electricity So what powers it?

Based on the mission it is assigned, and factors such as where the spacecraft is travelling, what it plans to do there and how long it needs to work engineers choose the best way to power a spacecraft.

The Sun                     

One source of power engineers consider is energy from the Sun, or solar power. Spacecraft that orbit close to Earth are dose enough to the Sun to use solar power. These spacecraft are fitted with solar panels, which convert the Sun’s energy into electricity. The electricity from the panels charges a battery in the spacecraft and can be used even when the spacecraft doesn’t have direct sunlight

Batteries

Sometimes, when the mission is only for a short duration, such as the Huygens probe that landed on Titan, Saturn’s largest moon, and meant to work only for a few hours, engineers may power the spacecraft with batteries. These batteries are designed to be tough since they need to withstand the harsh environment of space.

Atoms

An atom is a tiny building block of matter. Atoms need to store a lot of energy to hold themselves together. However, atoms such as radioisotopes are unstable and begin to fall apart. As they fall apart, they release energy as heat. A radioisotope power system uses the temperature difference between the heat from the unstable atoms and the cold of space to produce electricity. This system produces power for a very long time even in harsh environments. That’s why this system has been used to power many of NASA’s missions, including the two Voyager spacecraft that continue to send back information after over four decades in space.

Picture Credit : Google

Are Membrane mirrors for large space-based telescopes?

Researches create lightweight flexible mirrors that can be rolled up during launch and reshaped precisely after deployment.

Mirrors are a significant part of telescopes. When it comes to space telescopes, which have complicated procedures for launching and deploying, the primary mirrors add considerable heft, contributing to packaging difficulties.

Researchers have now come up with a novel way of producing and shaping large, high-quality mirrors. These mirrors are not only thinner than the primary mirrors usually employed in space-based telescopes, but are also flexible enough to be rolled up and stored inside a launch vehicle.

Parabolic membrane mirror

The successful fabrication of such parabolic membrane mirror prototypes up to 30 cm in diameter have been reported in the Optica Publishing Group journal Applied Optics in April. Researchers not only believe that these mirrors could be scaled up to the sizes required in future space telescopes, but have also developed a heat-based method to correct imperfections that will occur during the unfolding process.

Using a chemical vapour deposition process that is commonly used to apply coatings (like the ones that make electronics water-resistant), a parabolic membrane mirror was created for the first time. The mirror was built with the optical qualities required for use in telescopes. A rotating container with a small amount of liquid was added to the inside of a vacuum chamber in order to create the exact shape necessary for a telescope mirror. The liquid forms a perfect parabolic shape onto which a polymer can grow during chemical vapour deposition, forming the mirror base. A reflective metal layer is applied to the top when the polymer is thick enough, and the liquid is then washed away.

Thermal technique

The researchers tested their technique by building a 30-cm-diameter membrane mirror in a vacuum deposition chamber. While the thin and lightweight mirror thus constructed can be folded during the trip to space, it would be nearly impossible to get it into perfect parabolic shape after unpacking. The researchers were able to show that their thermal radiative adaptive shaping method worked well to reshape the membrane mirror.

Future research is aimed at applying more sophisticated adaptive control to find out not only how well the final surface can be shaped, but also how much distortion can be tolerated initially. Additionally, there are also plans to create a metre-sized deposition chamber that would enable studying the surface structure along with packaging unfolding processes for a large-scale primary mirror.

Picture Credit : Google

Are Saturn’s rings actually young?

The rings of Satum have fascinated and captivated humankind for over 400 years. It was in 1610 that Italian astronomer Galileo Galilei first observed these features through a telescope, though he had no idea what they were.

While our understanding of Saturn’s rings has matured over these four centuries, the age of these rings haven’t been determined precisely yet. The assumption that the rings likely formed at the same time as Satum draws flak as the rings are sparkling clean when compared to the planet.

A new study at the University of Colorado Boulder has provided the strongest evidence so far that the rings of Saturn are remarkably young. The research, published in May in the journal Science Advances, places the age of Saturn’s rings at around 400 million years old. When we compare this with Saturn itself, which is 4.5 billion years old, the rings are really young.

Studying dust                                                                        

The researchers arrived at this number by studying dust. By studying how rapidly the layer of dust built up on Saturn’s rings, they set out to put a date on it. It was, however, not an easy process.

The Cassini spacecraft provided an opportunity by arriving at Saturn in 2004 and collecting data until it intentionally crashed into the planet’s atmosphere in 2017. The Cosmic Dust Analyzer, which was shaped a little bit like a bucket and was aboard this spacecraft, scooped up small particles as the spacecraft whizzed by.

Just 163 grains

The researchers were able to collect just 163 grains of dust that had originated from beyond Saturn’s close neighbourhood during these 13 years. This quantity. however, was enough to make their calculations, placing the age of Saturn’s rings at a little less than 400 million years.

With this, we now know approximately how old Saturn’s rings are and that they are a relatively new phenomena in cosmic terms. With a previous study suggesting that Saturn’s rings could entirely disappear in another 100 million years, questions pertaining to how these rings were initially formed and why these short-lived, dynamic rings can be seen just now still remain.

Picture Credit : Google 

Which was the first successful soft landing on Mars?

Launched on May 28, 1971, Mars 3 was one among a pair of identical spacecraft. While its lander stopped transmitting data after less than 20 seconds, it nevertheless represents the first successful soft landing on Mars. A.S.Ganesh hands you the details about the Mars 3 mission…

When we talk about the space race between the Cold War adversaries the US. and the Soviet Union, we usually discuss the race to land the first human beings on the moon. Soon after this was achieved, however, attention shifted to our neighbouring planet Mars. The first successful soft landing on Mars was achieved by the Soviet Union with their Mars 3 mission.

At this initial period of planetary exploration, both these space superpowers tended to launch pairs of spacecraft as a precautionary measure. The idea was to have one as the backup. of another, so that at least one of them succeeded in its efforts even if the other failed completely in its objective.

It therefore comes as no surprise that the Mars 2 and Mars 3 missions consisted of identical spacecraft. With a bus/orbiter module and an attached descent/lander module, the combined mass of the spacecraft, with fuel, was approximately 4,650 kg. The Mars 3 spacecraft was 4.1 metres high. 5.9 metres across the two solar panel wings and had a base diameter of 2 metres.

Primary objectives

The primary objective of the Mars 3 orbiter was to image the martian surface and clouds. determine the temperature on Mars, and measure properties of the martian atmosphere. among others. These were in addition to serving as a communications relay to send signals from the lander to Earth.

Mars 3 was launched on May 28, 1971, just nine days after Mars 2 had been successfully launched. Ten days later, on June 8, a mid-course correction was made after which Mars 3 was involved in a three-way race with Mars 2 and U.S.’ Mariner 9 to become the first spacecraft to orbit Mars.

Even though Mariner 9 was last off the blocks, having been launched on May 30, it became the first to reach Mars on November 14. Mars 2 reached Mars on November 27 and Mars 3 made it to its destination on December 2.

Achieves soft landing

 Less than five hours before reaching Mars, the descent module of Mars 3 had been released. Having entered the martian atmosphere at roughly 5.7 km/s, a combination of aerodynamic braking, parachutes, and retro-rockets allowed the lander to achieve a soft landing. With the Mars 2 lander having crashed, this made the Mars 3 mission the first ever to achieve a soft landing on Mars.

Only just though, as the lander stopped transmitting and the instruments stopped working less than 20 seconds after the successful landing. While the reasons remain unknown, the massive surface dust storms that were raging at the time of landing could have caused the lander to stop working.

As the orbiter had suffered a partial loss of fuel, it couldn’t put itself into the planned 25 hour orbit. Instead, a truncated burn was performed by the engine in order to put the spacecraft into a 12 day, 19 hour long orbit about Mars.

20 orbits around Mars

A large volume of data was sent hack by Mars 2 and Mars 3 orbiters from December 1971 to March 1972, even though transmission continued till August. On August 22, 1972, an announcement was made stating that Mars 2 and Mars 3 had completed their missions. While Mars 2 had completed 362 orbits of the red planet, Mars 3 had performed 20 orbits.

Apart from the 60 images received from the probes, the data provided by them revealed mountains as high as 22 km, atomic hydrogen and oxygen in the upper atmosphere, and surface temperatures and pressures. The data gathered not only provided information on the martian gravity and magnetic fields, but also helped create surface relief maps.

Mars 3 was back in the news four decades later in April 2013 when citizen enthusiasts found features of its hardware in a five-year-old image from NASA’s Mars Reconnaissance Orbiter. The debris in the images resembled what might have been the parachute, heat shield, terminal retrorocket and lander. Regardless of whether these were the debris of the Mars 3 lander or not, the mission did successfully become the first ever to achieve a soft landing on our neighbouring red planet.

Picture Credit : Google 

When did Voyager 2 achieve its closest approach to Jupiter?

On July 9, 1979, Voyager 2 made its closest approach to the largest planet in our solar system. Now in interstellar space. Voyager 2 altered some of our ideas about the Jovian system.

The Voyager probes are: humanity’s longest running spacecraft as they have been flying since 1977 Both Voyager 2 and Voyager 1 are now in interstellar space, and though their power sources are gradually fading, they are still operational as of now.

It might seem counter-intuitive, but Voyager 2 was the first to be launched on August 20, 1977-about two weeks before the launch of Voyager 1. Both spacecraft were equipped with an extensive array of instruments to gather data. about the outer planets and their systems, in addition to carrying a slow-scan colour TV camera capable of taking images of the planets and their moons.

Based on Mariners

The design of the Voyagers was based on the Mariners and they were even known as Mariner 11 and Mariner 12 until March 7. 1977. It was NASA administrator James Fletcher who announced that the spacecraft would be renamed Younger. The Voyagers are powered by three plutonium dioxide radioisotope thermoelectric generators (RTGS) mounted at the end of a boom (a long metal beam extending from the spacecraft and serving as a structure subsystem).

Even though Voyager 1 was launched a little later, it reached Jupiter first in 1979 as it took a trajectory that put it on a faster path. Voyager 2 began transmitting images of Jupiter from April 24, 1979 for time-lapse movies of atmospheric circulation. For the next three-and-a-half months, until August 5 of that year, the probe continued to click images and collect data. A total of 17,000 images of Jupiter and its system were sent back to the Earth.

The spectacular images of the Jovian system included those of its moons Callisto, Europa, and Ganymede. While Voyager 2 flew by Callisto and Europa at about half the distance between the Earth and its moon, it made an even closer approach to Ganymede.

Ocean worlds

The combined cameras of the two Voyager probes, in fact. covered at least four-fifths of the surfaces of Ganymede and Callisto. This enabled the mapping out of these moons to a resolution of about 5 km.

Voyager 2’s work, along with observations made before and after, also helped scientists reveal that each of these moons were indeed an ocean world.

On July 9, 1979, the probe made its closest approach to Jupiter. Voyager 2 came within 6,45,000 km from the planet’s surface, less than twice the distance between Earth and its moon. It detected many significant atmospheric changes, including a drift in the Great Red Spot in addition to changes in its shape and colours.

Voyager 2 also relayed photographs of other moons like lo and Amalthea. It even discovered a Jovian satellite, later called Adrastea, and revealed a third component to the planet’s rings. The thin rings surrounding Jupiter, as had been seen by Voyager 1 as well, were confirmed by images looking back at the giant planet as the spacecraft departed for Saturn. As the probe used the gravity assist technique, Jupiter served as a springboard for Voyager 2 to get to Saturn.

Studies all four giant planets

 Four decades after its closest approach to Jupiter, Voyager 2 successfully fired up its trajectory correction manoeuvre thrusters on July 8, 2019. These thrusters, which had themselves last been used only in November 1989 during Voyager 2’s encounter with Neptune, will be used to control the pointing of the spacecraft in interstellar space.

In those 40 years, Voyager 2 had achieved flybys of Saturn (1981), Uranus (1986), and Neptune (1989), thereby becoming the only spacecraft to study all four giant planets of the solar system at close range. Having entered interstellar space on December 10, 2018, Voyager 2 is now over 132 AU (astronomical unit-distance between Earth and the sun) away from the Earth, still relaying back data from unexplored regions deep in space.

Picture Credit : Google

Membrane mirrors for large space-based telescopes?

Researches create lightweight flexible mirrors that can be rolled up during launch and reshaped precisely after deployment.

Mirrors are a significant part of telescopes. When it comes to space telescopes, which have complicated procedures for launching and deploying, the primary mirrors add considerable heft, contributing to packaging difficulties.

Researchers have now come up with a novel way of producing and shaping large, high-quality mirrors. These mirrors are not only thinner than the primary mirrors usually employed in space-based telescopes, but are also flexible enough to be rolled up and stored inside a launch vehicle.

Parabolic membrane mirror

The successful fabrication of such parabolic membrane mirror prototypes up to 30 cm in diameter have been reported in the Optica Publishing Group journal Applied Optics in April. Researchers not only believe that these mirrors could be scaled up to the sizes required in future space telescopes, but have also developed a heat-based method to correct imperfections that will occur during the unfolding process.

Using a chemical vapour deposition process that is commonly used to apply coatings (like the ones that make electronics water-resistant), a parabolic membrane mirror was created for the first time. The mirror was built with the optical qualities required for use in telescopes. A rotating container with a small amount of liquid was added to the inside of a vacuum chamber in order to create the exact shape necessary for a telescope mirror. The liquid forms a perfect parabolic shape onto which a polymer can grow during chemical vapour deposition, forming the mirror base. A reflective metal layer is applied to the top when the polymer is thick enough, and the liquid is then washed away.

Thermal technique

The researchers tested their technique by building a 30-cm-diameter membrane mirror in a vacuum deposition chamber. While the thin and lightweight mirror thus constructed can be folded during the trip to space, it would be nearly impossible to get it into perfect parabolic shape after unpacking. The researchers were able to show that their thermal radiative adaptive shaping method worked well to reshape the membrane mirror.

Future research is aimed at applying more sophisticated adaptive control to find out not only how well the final surface can be shaped, but also how much distortion can be tolerated initially. Additionally, there are also plans to create a metre-sized deposition chamber that would enable studying the surface structure along with packaging unfolding processes for a large-scale primary mirror.

Picture Credit : Google 

Why isn’t there an sound in space?

“In space, no one can hear you scream.” You may have heard this saying. It’s the tag line from the famous 1979 science fiction movie “Alien.” It’s a scary thought, but is it true? The simple answer is yes, no one can hear you scream in space because there is no sound or echo in space. I’m a professor of astronomy, which means I study space and how it works. Space is silent – for the most part.

How sound works

To understand why there’s no sound in space, first consider how sound works. Sound is a wave of energy that moves through a solid, a liquid or a gas. Sound is a compression wave. The energy created when your vocal cords vibrate slightly compresses the air in your throat, and the compressed energy travels outward.

A good analogy for sound is a slinky toy. If you stretch out a Slinky and push hard on one end, a compression wave travels down the Slinky. When you talk, your vocal cords vibrate. They jostle air molecules in your throat above your vocal cords, which in turn jostle or bump into their neighbours, causing a sound to come out of your mouth.

Sound moves through air the same way it moves through your throat. Air molecules near your mouth bump into their neighbours, which in turn bump into their neighbours, and the sound moves through the air. The sound wave travels quickly, about 1,223 kilometres per hour, which is faster than a commercial jet

 Sound in the solar system

Scientists have wondered how human voices would sound on our nearest neighbouring planets. Venus and Mars. This experiment is hypothetical because Mars is usually below freezing, and its atmosphere is thin. unbreathable carbon dioxide. Venus is even worse – its air is hot enough to melt lead, with a thick carbon dioxide atmosphere.

On Mars, your voice would sound tinny and hollow, like the sound of a piccolo On Venus, the pitch of your voice would be much deeper, like the sound of a booming bass guitar.The reason is the thickness of the atmosphere. On mars the thin air creates a high-pitched sound,and on venus the thick air creates a low-pitched sound. The team that worked this out simulated other solar system sounds, like waterfall on saturn’s moon titan.

Deep space sounds

While space is a good enough vacuum that normal sound can’t travel through it, it’s actually not a perfect vacuum, and it does have some particles floating through it. Beyond the Earth and its atmosphere, there are five particles in a typical cubic centimetre – the volume of a sugar cube- that are mostly hydrogen atoms.

By contrast, the air you are breathing is 10 billion billion (1019) times more dense. The density goes down with distance from the Sun, and in the space between stars there are 0.1 particles per cubic centimetre. In vast voids between galaxies, it is a million times lower still fantastically empty.

The voids of space are kept very hot by radiation from stars. The very spread-out matter found there is in a physical state called a plasma. A plasma is a gas in which electrons are separated from protons. In a plasma, the physics of sound waves get complicated. Waves travel much faster in this low-density medium, and their wavelength is much longer.

In 2022, NASA released a spectacular example of sound in space. It used X-ray data to make an audible recording that represents the way a massive black hole stirs up plasma in the Perseus galaxy cluster, 250 million light years from Earth. The black hole itself emits no sound, but the diffuse plasma around it carries very long wavelength sound waves.

The natural sound is far too low a frequency for the human ear to hear, 57 octaves below middle C which is the middle note on a piano middle of the range of sound people can hear. But after raising the frequency to the audible range, the result is chilling – it’s the sound of a black hole growling in deep space.

Space is a vacuum

So what about in space? Space is a vacuum, which means it contains almost no matter. The word vacuum comes from the Latin word for empty. Sound is carried by atoms and molecules, In space, with no atoms or molecules to carry a sound wave, there’s no sound. There’s nothing to get in sound’s way out in space, but there’s nothing to carry it, so it doesn’t travel at all. No sound also means no echo. An echo happens when a sound wave hits a hard, flat surface and bounces back in the direction it came from By the way, if you were caught in space outside your spacecraft with no spacesuit, the fact that no one could hear your cry for help is the least of your problems. Any air you still had in your lungs would expand because it was at higher pressure than the vacuum outside. Your lungs would rupture. In a mere 10 to 15 seconds, you’d be unconscious due to a lack of oxygen.

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What are the oldest surviving photographs of moon?

In March 1840, English-born American John William Draper clicked what are now the oldest surviving photographs of the moon. Using the daguerreotype process that had just been invented, Draper clicked the photograph that showed lunar features.

The smartphones in our hands these days are so powerful and equipped with great cameras that all we need to do to click a photograph of the moon is to wait for the moon to make its appearance and then take a photograph. It wasn’t always this easy though. In fact, the oldest surviving photographs of the moon are less than 200 years old. The credit for taking those photographs goes to English-born American scientist, philosopher, physician, chemist, historian and photographer John William Draper.

 Born in England in 1811, Draper went to the U.S. in 1832. After receiving a medical degree from the University of Pennsylvania, he moved to New York University in 1837 and was one of the founders of NYU’s School of Medicine in 1840. He not only taught there for most of his life, but also served as the president of the med school for 23 years.

Learns Daguerre’s process

 His interest in medicine, however, didn’t keep him away from dabbling with chemistry too. The chemistry of light-sensitive materials fascinated Draper and he learned about the daguerreotype process of photography after the news arrived in the U.S. from Europe. French artist and photographer Louis Daguerre had invented the process only in 1839.

Draper attempted to improve the photographic process of Daguerre and succeeded in ways to increase plate sensitivity and reduce exposure times. These advances not only allowed him to produce some of the best portrait photographs of the time, but also let him peer into the skies to try and capture the moon.

He met with failure in his first attempts over the winter of 1839-40. He tried to make daguerreotypes of the moon from his rooftop observatory at NYU, but like Daguerre before him, was unsuccessful. The images produced were either underexposed, or were mere blobs of light in a murky background at best.

Birth of astrophotography

 By springtime in March 1840, however, Draper was successful, thereby becoming the first person ever to produce photographs of an astronomical object. He was confident enough to announce the birth of astrophotography to the New York Lyceum of Natural History, which later became the Academy of Sciences. On March 23, 1840, he informed them that he had created a focussed image of the moon.

The exact date when he first achieved it isn’t very clear. While the photograph on loan to the Metropolitan Museum of Art (which cannot be shown here due to rights restrictions) is believed to have been clicked on March 16 based on his laboratory notebook, the one pictured here was by most accounts on the night of March 26, three days after he had announced his success. The fact that many of Draper’s original daguerreotypes were lost in an 1865 fire at NYU, and that daguerreotype photographs themselves don’t have a long shelf life unless well-preserved from the moment they were taken means that the ones remaining become all the more significant.

The moon pictured here shows an extensively degraded plate with a vertically flipped last quarter moon, meaning the lunar south is near the top. This shows that Draper used a device called the heliostat to keep light from the moon focussed for a 20-minute-long exposure on the plate. They are of the same we and same circular image area as that of his first failed attempts.

Conflict thesis

Apart from being a physician and the first astrophotographer, Draper also has other claims to fame. He was the invited opening speaker in the famous 1860 meeting at Chford University where English naturalist Charles Darwin’s ‘Origin of Species’ was the subject of discussion. He is also well known for his book ‘A History of the Conflict between Religion and Science’ which was published in 1874. This book marks the origin of what is known as the “conflict thesis” about the incompatibility of science and religion.

While we will probably never know on which particular March 1840 night Draper captured the first lunar image, his pioneering achievement set the ball rolling for astronomical photography. The fact that he achieved it with a handmade telescope attached to a wooden box with a plate coated with chemicals on the back makes it all the more remarkable.

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What is the mysterious object in the James Webb telescope?

A team of international astrophysicists has discovered many mysterious objects that were hidden in images from the James Webb Space Telescope. These include six potential galaxies that should have emerged so early in the history of the universe and are so massive that they should not be possible under current cosmological theory.

These candidate galaxies may have existed roughly 500 to 700 million years after the Big Bang. That places them at more than 13 billion years ago, close to the dawn of the universe. Containing nearly as many stars as the modern-day Milky Way, they are also gigantic. The results of the study have been published in the journal Nature in February

Not the earliest discovered

 Launched in December 2021, the James Webb Space Telescope is the most powerful telescope ever sent into space by us. The candidate galaxies identified this time from its data, however, aren’t the earliest galaxies observed by Jams Webb. Another group of scientists spotted four galaxies observed that likely formed 350 million years after the Big band. Those galaxies, however, were nowhere as massive as the current findings.

While looking at a stamp-sized section of an image that looked deep into a patch of sky close to the Big Dipper (a constellation, also known as the Plough), a researcher spotted fuzzy dots that were way too bright and red. In astronomy, red light usually equals old light. As the universe expands the light emitted by celestial objects stretches, making it redder to human instruments.

Based on their calculations, the team was also able to suggest that the candidate galaxies they had discovered were also huge. Containing tens to hundreds of billions of sun-sized stars worth of mass, these were akin to our Milky Way.

Might rewrite astronomy books

As current theory suggests that there shouldn't have been enough normal matter at that time to form so many stars so quickly, proving it might rewrite astronomy books. And even if these aren't galaxies, then another possibility is that they are a different kind of celestial object, making them interesting.

For now, the discovery has piqued the interest of the researchers and the astronomical community. More data and information about these mysterious objects from James Webb is what is being sought after to confirm that these candidate galaxies are actually as big as they look, and date as far back in time.

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How about learning a bit about the stellar world?

Every star is a giant, bright ball of hot gas. Ever wondered how the stars form and how they die eventually? How about learning a bit about the stellar world?

One septillion stars, that’s almost the number of stars estimated to exist in our universe, Our Milky Way alone contains more than 100 billion stars. The nearest star to us is our Sun. Every star is a giant ball of hot gas. They are the building block of galaxies. “We are made of star stuff,” said noted astronomer Carl Sagan. It means that whatever we are composed of whatever our physical bodies are made of the raw materials that make up our physical bodies were created from the matter from long-extinguished stars. How about learning a bit about the stellar world?

Stars and their birth

Stars are made of huge balls of hot gas it is largely composed of hydrogen and small parts of helium and a few other elements. The star is held together because of its own gravity.

Every star goes through its own unique life cycle. Stars are born within hinge clouds of dust and gas called molecular clouds and are scattered throughout the galaxies. The gas in the molecular clouds clump together, forming high-density pockets, and often collide with each other. With each collision, more matter gets added to it and its mass grows. The gravitational force becomes stronger. The clumps of gas and dust then collapse under their own gravitational attraction. As this happens, the material heats up because of the friction and leads to the formation of a protostar which is also called the baby star. The set of stars newly formed from molecular clouds are called stellar clusters.

Life of a star

The energy of a protostar is derived from the heat released by its initial collapse. As years pass by, the high pressure and temperature inside the core of the star lead to a nuclear fusion reaction, where the nuclei of hydrogen atoms combine together to form helium. The energy that gets released post-nuclear fusion is enough to prevent it from collapsing under gravity.

At any time, there are two opposing forces acting on a star that prevent it from collapsing. There is the gravity of the star which tries to shrink the star, while the energy released following the nuclear fusion in the stars core leads to outward pressure. This outward push will resist gravity’s inward squeeze.

When a star is in the phase of undergoing a nuclear fusion reaction, it is called a main sequence star. This is also the longest phase of the star’s life. It has to be noted that as time passes, that is over millions of years, the size, luminosity and temperature of the star also change. The gas in the star is its fuel and its mass determines how long the star will live. This is because a massive star will end up burning a lot of fuel at a higher rate to generate enough energy to prevent it from collapsing: Meanwhile, lower mass stars will burn longer and shine for longer periods, some trillions of years whilst the massive ones may live for just about a few million years.

How does a star die?

When the star runs out of hydrogen to convert into helium, it marks the beginning of the end of the star’s life. Its core collapses leading to the death of the star. A star’s death is largely dependent on its mass. In the case of a lower-mass star, its atmosphere will keep on expanding until it becomes a giant star and the helium gets converted into carbon in its core. Over time the outer layers of the star will get blown off and the cloud of gas and dust expands. This expanding cloud is called a planetary nebula. All that is left now is the core. This is called a white dwarf star which will cool off over the following billions of years.

But what happens in the case of a high-mass star? The fusion leads to the conversion of carbon into heavier elements which then fuel the core. This process produces enough energy to prevent the core from collapsing. This goes on for a few million years until the star runs out of fuel. This is followed by a supernova explosion. The core either becomes a neutron star or a black hole

The supernova explosion is the biggest explosion that occurs in space. It releases material into the cosmos and this matter will then form part of the future molecular clouds and thereby become part of the stars.

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What has the Cassini spacecraft discovered about Saturn?

Saturn’s moon now satisfies what is usually considered the strictest requirement for life

The search for extraterrestrial life is now more serious than probably ever before. And the search just got more exciting with a team of scientists discovering new evidence that the subsurface ocean of Enceladus – Saturn’s moon- contains a key building block for life phosphorus.

The Cassini spacecraft explored Saturn and its system of rings and moons for more than 13 years. Based on data obtained from this mission, the research team directly found phosphorus in the form of phosphates originating from the ice-covered global ocean on the moon. The results were published in the journal Nature in June.

Our fate and phosphates

In the form of phosphates, phosphorus is necessary for all life on Earth. Be it the creation of DNA and RNA, or the bones and teeth in animals and human beings, life as it is today is impossible without phosphates.

Once the Cassini spacecraft discovered the subsurface liquid water on Saturn’s moon Enceladus, it then analysed samples of ice grains and gases erupting from cracks on Enceladus’ surface. When salt-rich ice grains were analysed by Cassini’s Cosmic Dust Analyzer, it showed the presence of sodium phosphates.

Life beyond Earth

The team’s observational results along with laboratory analogue experiments thus suggest that phosphorus is readily available in Enceladus as phosphates. This makes the discovery a major step forward in the search for life beyond our own Earth.

While worlds like our Earth with surface oceans have to reside in a narrow range of distances from their host stars (to maintain temperatures that support surface water), interior ocean worlds can occur over a large range of distances. This is true within our solar system and beyond. The presence of phosphates in Enceladus thereby increases the number of habitable worlds potentially possible across the galaxy.

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What’s the great Attractor?

In the depths of the cosmic ocean, there is a strange force that keeps pulling our galaxy towards it. And inevitably, whatever is near our Milky Way, including nearby galaxies, are being drawn towards this unknown force.

But for the longest time, we couldn’t understand what was the cause of this force or what lay here as this portion of the universe where the attraction is being felt is hidden from our view all thanks to our own galaxy. The force that is pulling the Milky Way lies in the direction of the constellation Centaurus. And the Milky Way’s disk blocks out our view here.

This region, which we can’t look through (with telescopes) from our galaxy, has been called the Zone of Avoidance. And the Great Attractor sits right here, at this 20% of the universe that’s shielded from us.

The only way to get a glimpse of this area is by using X-rays and infrared light.

It was in the 1970s that the Great Attractor was first discovered. It happened when astronomers made detailed maps of the Cosmic Microwave Background (that is, the light left over from the early universe). It was observed that one side of the Milky Way was warmer than the other.

This indicated that the galaxy was vigorously moving through space. The speed was observed to be about 370 miles per second (600 km/s). While astronomers could measure the high speed at which the galaxy was moving, they couldn’t explain its cause or origin.

The Great Attractor is a region of great mass that exerts an immense gravitational pull on our galaxy and surrounding galaxies. It is estimated to have a diameter of about 300 million light-years. It is estimated to be between 150 and 250 million light years away from Earth.

It sits at the centre of a local Supercluster known as the Laniakea Supercluster.

In short, the Great Attractor is the gravitational centre of the Laniakea Supercluster which consists of our galaxy and 100,000 others.

It is not a celestial body, but rather a point in the universe where everything gets attracted to.

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What is a planet beyond our solar system called?

A planet beyond our own solar system is referred to as an exoplanet. While most exoplanets orbit other stars, there are also free-floating exoplanets, called rogue planets, that are not tethered to any star and orbit the galactic centre.

“Blind” surveys

Traditionally, ground-based means have been employed to detect exoplanets. Astronomers use “blind” surveys to look for stars in the sky with the potential for housing giant planets, which can then be directly imaged from Earth based on the stars age and distance. This technique, however, has a very low yield, meaning that exoplanets are detected very infrequently. Astronomers have developed a new technique to detect exoplanets whose portraits can be taken using large ground-based telescopes on Earth. They have tasted success with this method and the result is the direct image of a Jupiter-like gas giant – HIP 99770 b-132.8 light years away in the Cygnus constellation. The study behind this success was published in the journal Science in April.

Combining astrometry and direct imaging

HIP 99770 b is the first exoplanet detected by combining astrometry and direct imaging. While two observatories on Hawaii Island did the direct imaging, the astrometry- responsible for measuring the position and motion of HIP 99770 b’s home star – came from Gaia space observatory and its predecessor Hipparcos.

Precision astrometry is the method of detecting the movement of stars. This allows researchers to identify those stars that are tugged at by the gravitational pull of an unseen companion like a planet. A picture of the star systems that are close enough is then captured to directly image.

The detection of HIP 99770 b serves as proof of a concept developed by an international research team. They were also able to determine that this exoplanet is 14-16 times the mass of Jupiter and orbits a star that is almost twice as massive as our sun. It receives a similar amount of light as Jupiter as its host star is far more luminous than the sun. The team characterised the nature of HIP 99770 b’s atmosphere and showed that the planet’s atmosphere has signs of water and carbon monoxide.

This new method of searching for exoplanets is believed to be a major improvement to the existing, traditional method of “blind” surveys. The researchers also hope that this new approach would lead to further advances that eventually lead to the discovery of an Earth-twin around a nearby star.

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A test flight with a number of firsts

The 1960s were a rather exciting time if you were part of NASA. After U.S. President John F. Kennedy stated his goal of landing humans on the moon and returning them safely home before the end of the decade of the 1960s, work at NASA progressed at breakneck speed given the enormity of the task ahead of them.

There were a lot of successes along the way, and setbacks too that proved to be equally important in terms of the overall learning. The Apollo-Saturn (AS) 201 mission in the mid 1960s was one such test flight that had a number of firsts, but also experienced malfunctions.

"All-up" philosophy

Coming at the height of Project Gemini, the AS-201 served as a crucial milestone in our march towards the moon. It used the "all-up" philosophy, according to which all components of a system were tested in a single first flight.

A suborbital test flight, its goals included demonstrating the Saturn IB's capabilities, the operation of Apollo Service Module's (SM) main engine, and determining the effectiveness of the Command Module's (CM) heat shield. The Saturn IB rocket, which was built on the 10 successful launches of Saturn 1 rocket, was the most powerful rocket up to that time.

Construction of the AS-201 spacecraft began in 1963 at the North American Aviation (NAA) plant in California. Assembly for the mission began in 1965 with the Saturn IB first stage arriving at the Cape Kennedy Air Force Station (CKAFS), now the Cape Canaveral Space Force Station, on August 14.

Extensively tested

The CM and SM of the spacecraft arrived within two days of each other in October. After successful mating of the two modules and extensive testing, they were trucked to the launch pad and stacked on top of the rocket by December. By January 1966, the final pieces were in place, and the rocket and spacecraft were declared ready for its mission after a flight readiness review and a countdown demonstration.

On February 26, 1966, the AS-201 mission lifted off after a number of launch delays. With flight director Glynn S. Lunney at the helm, a team of engineers kept an eye on all aspects of the mission.

Both stages of the Saturn IB rocket performed well and the Apollo Command and Service Module (CSM) was placed in its suborbital trajectory, with a peak altitude of 488 km. A camera mounted inside the first stage was later recovered at sea, and it had captured some key moments, including the fiery stage separation.

Helium ingestion in propellant lines, however, resulted in lower thrust than predicted during the first burn and the same problem also affected a second burn to test the engine's restart capability. The Service Propulsion System engine also underperformed, meaning the CM entered the atmosphere at a velocity slower than that planned.

Additionally, the capsule rolled during reentry as an electrical fault in the CM led to a loss of steering. The heat shield performed its duties without any flaws despite all these setbacks and the spacecraft splashed down in the Atlantic Ocean, 75 km from the intended target.

On museum display

The largely successful 37-minute test flight travelled 8,472 km overall. The CM was retrieved by swimmers from the prime recovery ship and it was then sent to the NAA plant for postflight inspections. After using it for land impact tests, NASA donated the capsule, which is now on loan and is displayed at the Strategic Air Command and Aerospace Museum.

The Saturn IB is now largely forgotten as its efforts pale in comparison with the Saturn V rocket, one of the largest and most powerful rockets built and which successfully sent people to the moon. But the Saturn IB rocket and the AS-201 mission were all part of the small stepping stones that made the giant leap possible.

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It’s time for a star party

The sky and the flock of stars that flicker endlessly have always been an inspiration for mankind. Some 400 years ago, on a starry night, Italian astronomer Galileo Galilei aimed his telescope towards the sky. That was just the beginning of modern astronomy. Stargazing is the start of an incredible journey towards exploring the cosmos, which will help you learn more about the universe we are living in.

Look at the stars. Look how they shine for you…" sang Coldplay's lead singer Chris Martin in the song "Yellow" which was part of their debut album "Parachutes". Legend has it that the inspiration for the song came when Martin and his bandmates were asked to look at the stars. The band had just finished recording the song "Shiver" and was taking a break when the song's co-producer Ken Nelson asked them to look at the stars. A melody popped into Martin's head. And "Yellow" was born.

The sky and the gaggle of stars that flicker endlessly have always been an inspiration for mankind. It is our window to space and every cosmic body out there. The quest to explore the stellar world dates back centuries.

The start of modern astronomy

Some 400 years ago, on a starry, starry night, Italian astronomer Galileo Galilei aimed his telescope towards the sky. He was the first to use the earliest version of the telescope, his own version of the "spyglass" (a device used to see far away objects) to observe celestial bodies.

He documented what he saw and made discoveries that changed how we perceived the Cosmos. Observing the night sky, he found out that the Moon had mountains and pits, and that Jupiter had moons. That was just the start of modern astronomy.

The compelling need to watch the Moon or the many astral bodies in a star-spangled sky has no rhyme or reason. So if you like the sky and stars, read on.

The art of stargazing

Stargazing is just the start of an incredible journey towards exploring the cosmos, which will help you learn more about the universe we are living in. Every astronomer started off as an enthusiastic stargazer.

Stargazing or amateur astronomy is the practice of watching the stars and other celestial bodies. It can be a rewarding hobby that lets you disconnect from the chores of your routine life and connect with the vast universe.

The first thing to ensure is that you have a clear, dark sky. without light pollution. It is difficult to enjoy the sky and stars if you live in a well-lit area, where light is directed towards the sky. Once you get a clear, dark sky, just look up and befriend the sky.

Observing the sky

You do not need expensive telescopes to see the celestial bodies. All you need to do is look up. The naked eye can guide you well enough. What you might need though is a sky map that can help you identify the many stars and constellations (groups of stars that look like patterns).

Once you correctly identify a star or a constellation, your journey gets more exciting. As many as 88 constellations cover the sky. Try to make out easily recognisable star patterns or constellations such as the Orion, Cassiopeia, Big Dipper/Ursa Major, Ursa Minor, Pegasus and Taunus.

Did you know that some planets are visible to the naked eye? Planets thus visible are Venus, Mercury, Mars, Saturn, and Jupiter.

The brightest star in the night sky is Sirius. But how do you know if you are looking at a planet or a star? Stars have their own light, whilst planets do not. Planets only reflect the light from the Sun and do not twinkle.

Befriend the sky

What you see in the sky, depends on where you are located on Earth. As Earth orbits the Sun, the stars also shift. Once you have understood this, you will know that even as the stars shift as our planet moves, they tend to return to the same spot in the sky every year. Have a journal and make a note of everything you observe in the sky.

One way to get better at spotting the stars and learning about them is to join star parties or go to your nearest observatory. Star parties are events where stargazers join to watch the stars and the sky using telescopes. You can look at the skies using a telescope in observatories as well. You can also join local astronomy clubs. Your school might even have one. If not why don't you take an initiative to start one? Alternatively, you can download mobile applications that help you identify the stars and planets.

As you progress, you can invest in a decent pair of astronomical binoculars that will help you see the celestial bodies up close. For instance, many craters on the moon that you have seen only in pictures become crystal clear as you peer through the binoculars.

Did you know that there is even a global movement to protect the dark sky? So what are you waiting for? The sky is calling. And you must go.

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What’s a binary star system?

When two stars orbit a common centre of mass, they are called binary stars. These stars are gravitationally bound to each other. It is said that 85% of stars are in binary systems or in multiple systems.

Did you know that the light that we observe coming from a star in the sky may not be produced by a single star? That the light emanating from the single point may actually be light coming out from two or even more stars that are orbiting together? These are called multiple-star systems.

The most common star system that you come across will be a binary star system that comprises two stars. When two stars orbit a common centre of mass, they are called binary stars. These stars are gravitationally bound to each other.

Did you know that most stars are in binary systems? It is said that 85% of stars are in binary systems or in multiple systems.

While the brighter star is called the primary star, the dimmer one is called the secondary. If the stars are of equal brightness, then the discoverer gets to decide on the designation.

Binary stars are very important from an astronomic point of view as they help in understanding stellar evolution. They help determine the masses and luminosities of stars.

But how are these binary stars formed? The most common way of formation of a binary star system is by a process called fragmentation.

According to this, the gas and dust cloud which collapses to form a star splits into two or more stars due to their instability or cooling/heating effects.

These fragments or stars then evolve separately and form the binary star system. But there are rare incidents when a massive star captures a passing one, as the star travels through the galaxy and thereby creates a new binary pair.

Binary pairs can be classified based on a number of factors. One such classification is on how they are observed viz. visual binaries.

They are called visual binaries when the two stars have a wide separation when viewed through a telescope.

The first binary stars to be ever spotted were visual binaries. In 1617, at the behest of a scientist, Italian astronomer Galileo Galilei used his telescope to focus on a star at the end of the handle of the Big Dipper, a constellation.

It was discovered that this wasn’t a single star, but two stars which later turned out to be six. Sir William Herschel, who is known for cataloguing 700 pairs of stars, used the term binary for the first time in 1802 to refer to the double stars.

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Sci-fi novels that shaped reality

Science fiction (sci-fi) and scientific innovation have been intertwined since the creation of this genre. Here are five marvellous inventions that were inspired by sci-fi.

The Taser

The Taser stun gun is a hand-held electrical non-lethal weapon used by police and law enforcement officers around the world. Invented by Jack Cover, an American aerospace scientist in the 1960s-70s, this device takes inspiration from English writer Victor Appleton’s young adult sci-fi novel ‘Tom Swift and His Electric Rifle (1911)’. The purpose of creating this device was to provide an alternative to the firearms that the air marshals were supposed to carry and use in case of a hijack. This invention was a solution to the concern that firing a gun on a plane could damage important and sophisticated machinery or pierce the fuselage.

Cover’s invention pays homage to Appleton’s book, and its name TASER is an acronym for Thomas A. Swift’s Electric Rifle. The scientist is said to have added the ‘A’ to make the word easier to pronounce.

Liquid-fuelled rockets

The idea of rockets, space travel, and exploration might not sound exceptionally futuristic today, but for 16-year-old Robert H. Goddard coming across this idea for the first time in English novelist H.G. Wells’s ‘The War of the Worlds’ (1898) was something right out of a dream. The famed father of rocketry invented and launched the world’s first liquid-fuelled rocket in 1926, making space travel a reality. A few years after this momentous event, the NASA physicist penned a letter to Wells elaborating on the “deep impression” his novel made on the American inventor and motivated him to take this journey “aiming at the stars” both literally and figuratively.

World Wide Web

Millions of people across the globe use the World Wide Web every day. They access it through computers, phones and other digital devices. From ordering food to sharing one’s location or some news and pictures with others, we use the Web all the time.

The first proposal for the World Wide Web was written by Tim Berners-Lee in 1989. Talking about the motivation behind this invention, the English computer scientist said, “I believe If you connect people up and you take away the national boundaries and you just leave humanity connected, it will naturally become better.” He also credited Arthur C. Clarke’s short story ‘Dial F’ for Frankenstein as the inspiration behind the World Wide Web. Acknowledging the impact of his story on Berners-Lee, the English sci-fi writer declared, “I guess I am the godfather of the World Wide Web.”

Humanoid robots ASTRO BOY

Japan’s Tomotaka Takahashi is one of the world’s leading new-generation robot scientists. In 2013, his humanoid robot named Kirobo became the world’s first talking robot sent into space to keep astronauts company. Talking about his passion for robotics in an interview, Takahashi said “When I was about six, I started reading the manga comic ‘Astro Boy’ after finding it lying around at home. My dream, from that moment on, was to become a robot scientist. I made my first robot around the same time, from a soapbox and duct tape complete with a robot face.” Osamu Tezuka’s ‘Astro Boy’ is a manga series that ran from 1952 to 1968. It chronicles the adventures of the titular humanoid. The Japanese scientist also admitted that his 13-inch-tall robot Kirobo’s design and colour palette are heavily inspired by the friendly manga character.

Helicopter

Since the beginning of time, the idea of flying from one place to another in little time has been a fascinating topic. The helicopter is one of the many inventions that aimed to accomplish this. Russian-American aviator Igor Sikorsky is credited with inventing the modern helicopter. As a child, his parents exposed him to the technical drawings of da Vinci and encouraged him to pursue science. As a curious kid growing up in Russia, he was fascinated by Jules Verne’s 1886 novel ‘Robur the Conqueror (which is also known as The Chipper of the Clouds)’. This book’s description of a flying machine called the ‘Albatross’ inspired Sikorsky’s design of the helicopter. Starting test flights in 1939, Sikorsky’s aircraft was ready for larger production by 1942.

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What was the Mercury space capsule project?

On June 11, 1963, the Mercury space capsule was patented and assigned to NASA. The patent was received less than a month after the last flight of Project Mercury had been carried out.

Receiving a patent generally signals a major milestone. As an exclusive right granted for an invention, be it a product or a process, it usually denotes a new way of doing something, thereby becoming important. In the case of the Mercury space capsule, however, the patent came closer to the end.

Project Mercury was conceived as a NASA programme to put the first American astronauts in space. Named after a Roman god who was very fast, the project notched up many successes. At the centre of this success was the Mercury space capsule.

“Space capsule”

The principal designer of the Mercury spacecraft was Maxime Faget, a mechanical engineer who also contributed to the designs of the Gemini and Apollo spacecraft. Faget, along with Andre Meyer, Robert Chilton, Willard Blanchard Jr., Alan Kehlet, Jerome Hammack and Caldwell Johnson filed for a patent titled “Space capsule” on October 16, 1959.

In this patent application, they described their invention relating to space vehicles as a “manned capsule configuration capable of being launched into orbital flight and returned to the Earth’s surface.”

Additionally, it was capable of providing “protection for its occupant from the deleterious effects of large pressure differentials, high temperatures, micrometeorite collisions, high level acoustical noise, and severe inertial and impact loads.”

Not cosy

It did all that, but the capsule was a rather small one, with room for just one astronaut. What’s more, this astronaut had to stay seated throughout the flight. While there was very little room for even the single seated astronaut to make any movements, it was argued that not much was required as the pilot would only need to move his arms and head, and was to never leave the spacecraft during flight.

Following uncrewed flights and those with primates as part of Project Mercury, the first crewed flight took place on May 5, 1961. Alan Shepard made the first crewed Mercury flight in a capsule that he named Freedom 7. The 15-minute flight that went into space and came back down made him the first American in space.

Between 1961 and 1963, there were six successful flights as part of Project Mercury that showed that Americans could fly in space. While two of these flights were suborbital flights (reached space and came right back down), the other four made it into orbit and circled our Earth.

Every time the Mercury spacecraft re-entered the Earth’s atmosphere, the blunt end came in first to not only slow down the spacecraft, but also shed the heat caused by friction with the air during the descent. With layers of heat resistant ablative resins coating the curved heat shield, it charred away to minimise structural heating, preventing damage to the spacecraft, and of course, protecting the crewman.

The last of the six successful crewed Mercury Project spaceflight took place on May 15, 1963. Each of these flights lasted from 15 minutes to 34 hours, with most lasting less than nine hours.

Just a formality

This meant that by the time the patent for the Mercury capsule was awarded on June 11, 1963, it had already been put to use multiple times successfully, with each of the successes celebrated by an entire country. The patent, which was assigned to NASA, was merely a formality.

In fact, NASA retired the Mercury capsule in the same week in which the patent was awarded. The first manned space vehicle of the U.S. was retired with honours of course, having been central to a project that came at the height of the space race between the U.S. and the Soviet Union.

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What is the streak of light that shoots across the night sky called?

During Earth’s journey around the Sun, there are times when its orbit crosses the orbit of a comet. It is when the planet moves through the comet debris trail that we witness meteor showers. The showers are named after the star or constellation which is close to where the meteors appear to radiate in the sky.

All of us may have seen streaks of light zip through the sky. We call them shooting stars and we also wish upon them. Well, what are these shooting stars? What are these streams of light?

Consider the objects in space. These are lumps of rock or objects in space with sizes ranging from grains to small asteroids. A small piece of a comet or asteroid is called a meteoroid.

Meteoroid

These meteoroids can be considered as space rocks. They orbit the sun and when they enter Earth’s atmosphere at a high speed, they burn because of frictional heating, causing the light. These rays of light are referred to as meteors.

When many meteors appear at once, we call it a meteor shower. During a meteor shower, a number of meteors can be seen radiating or originating from a point in the night sky.

But where do these meteoroids come from? How does Earth come across these? During Earth’s journey around the Sun, there are times when its orbit crosses the orbit of a comet. It is when the planet moves through the comet debris trail that we witness meteor showers.

The meteor showers are named after the star or constellation which is close to where the meteors appear to radiate in the sky.

The Perseids meteor shower is the most famous meteor shower and they peak around August 12 every year.

Other notable meteor showers include the Leonids, Aquarids and Orionids and Taurids.

Now what happens when meteoroid survives the journey through the Earth’s atmosphere and hits the ground? In that case, it becomes a meteorite.

Did you know that more than 50,000 meteorites have been found on Earth?

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What does a dust devil sound like on Mars?

Mars rover’s microphone captures ten seconds of rumbling noise created by dust devil on the Red Planet. It’s the same microphone that provided the first sounds of Martian wind in 2021.

What does a dust devil sound like on Mars? A NASA rover by chance had its microphone on when a whirling tower of red dust passed directly overhead, recording the racket.

It’s about 10 seconds of not only rumbling gusts of up to 40 kph, but the pinging of hundreds of dust particles against the rover Perseverance. Scientists released the first-of-its-kind audio. It sounds strikingly similar to dust devils on Earth, although quieter since Mars’ thin atmosphere makes for more muted sounds and less forceful wind, according to the researchers.

The dust devil came and went over Perseverance quickly last year, thus the short length of the audio, said the University of Toulouse’s Naomi Murdoch, lead author of the study appearing in Nature Communications.

At the same time, the navigation camera on the parked rover captured images, while its weather-monitoring instrument collected data.

“It was fully caught red-handed by Persy,” said co-author German Martinez of the Lunar and Planetary Institute in Houston.

Photographed for decades at Mars but never heard until now, dust devils are common at the red planet.

This one was in the average range: at least 400 feet (118 metres) tall and 80 feet (25 metres) across, travelling at 16 feet (5 metres) per second.

The microphone picked up 308 dust pings as the dust devil whipped by, said Murdoch, who helped build it.

Given that the rover’s SuperCam microphone is turned on for less than three minutes every few days, Murdoch said it was “definitely luck” that the dust devil appeared when it did on Sept. 27, 2021. She estimates there was just a 1-in-200 chance of capturing dust-devil audio. Of the 84 minutes collected in its first year, there’s “only one dust devil recording,” she wrote in an email from France.

WHAT IS A DUST DEVIL?

  • Common across Mars, dust devils are short-lived whirlwinds loaded with dust that form when there is a major difference between ground and air temperatures.
  • They are a common feature in the Jezero crater, where the Perseverance rover has been operational since February 2021 – but it had never before managed to record audio of one of them.
  • By chance on September 27, 2021, a dust devil 118 metres high and 25 metres wide passed directly over the rover.
  • This time, the microphone on the rover’s SuperCam managed to catch the muffled, whirring sounds.

Sounds…so far

  • The same microphone on Perseverance’s mast provided the first sounds from Mars namely the Martian wind soon after the rover landed in February 2021.
  • It followed up with audio of the rover driving around and its companion helicopter, little Ingenuity, flying nearby, as well as the crackle of the rover’s rock-zapping lasers, the main reason for the microphone.

ROCK SAMPLES

On the prowl for rocks that might contain signs of ancient microbial life, Perseverance has collected 18 samples so far at Jezero Crater, once the scene of a river delta. NASA plans to return these samples to Earth a decade from now. Its helicopter Ingenuity has logged 36 flights, the longest lasting almost three minutes.

CAN ACOUSTIC DATA SOLVE THE MARTIAN MYSTERY?

  • These recordings allow scientists to study the Martian wind, atmospheric turbulence and now dust movement as never before.
  • The impact of the dust-made “tac tac tac sounds will let researchers count the number of particles to study the whirlwind’s structure and behaviour.
  • It could also help solve a mystery that has puzzled scientists. On some parts of Mars, whirlwinds pass by sucking up dust, cleaning the solar panels of rovers along the way.
  • Understanding why this happens could help scientists build a model to predict where the whirlwinds might strike next.
  • It could even shed light on the great dust storms that sweep across the planet, famously depicted in the 2015 science-fiction film “The Martian”.

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What was the mission of the Hubble Space Telescope?

A mission conceived as one for preventive maintenance turned out to be more urgent after four of the six gyroscopes on board the Hubble space telescope failed.

The Hubble space telescope has changed our understanding of the universe A telescope that was launched into low Earth orbit in 1990, Hubble still remains operational and continues to be a vital research tool. Following NASA’s most recent review of Hubble’s operations, it has been announced that NASA would support the observatory through June 2026, with estimates suggesting that it might be able to continue operations until the mid-2030s and even beyond.

Designed to be visited

While the longevity of the telescope is testament to the vision of those who conceived the mission, there’s another crucial factor that has made it possible. Hubble was the first telescope that was designed to be visited in space. This meant that astronauts could not only perform repairs and replace parts, but also upgrade its tech with newer instruments. There have been five such missions that have taken place from 1993 to 2009. One such servicing mission in December 1999 turned out to be a life saver for the telescope.

After the first servicing mission in 1993 and the second one in 1997, the third to carry out preventive repairs was scheduled for June 2000. Since Servicing Mission 2 in February 1997, however, three of the six gyroscopes aboard Hubble had failed. With at least three working gyroscopes necessary for Hubble’s operation, it prompted the managers to split Servicing Mission 3 (SM3) into two parts, SM3A and SM3B, with the former scheduled for December 1999.

An unexpected failure

 On November 13, 1999, a fourth gyroscope failed unexpectedly. With SM3A planned for the following month, this triggered NASA to place Hubble into safe mode. The safe mode was a sort of protective hibernation that prevented the telescope from making any observation. Hubble was in this state for over a month, waiting for the crew of SM3A to make their way.

With servicing mission veterans Steven Smith and Michael Foale at the helm, the seven-member crew aboard the Discovery Space Shuttle (STS-103) left for space on December 19. Within a couple of days, they manoeuvred close enough to Hubble such that it could be grappled with Discovery’s robotic arm.

All six gyroscopes replaced

 The first of the three scheduled spacewalks took place over 8 hours and 15 minutes spanning December 22-23 (Central European Time, CET). Smith, along with fellow crew member John Grunsfeld, managed to replace all six of Hubble’s gyroscopes. The entire astronomical community heaved a collective sigh of relief on receiving this news. The duo also replaced kits to prevent Hubble’s batteries from overcharging.

While Hubble’s main computer was changed in the second spacewalk that spanned 8 hours 10 minutes through December 23-24 (CET), the final spacewalk spanning 8 hours 8 minutes through December 24-25 (CET) saw a faulty transmitter and data tape recorder being replaced. Preliminary tests were then conducted to ensure that all of Hubble’s systems, be it old or new, were performing satisfactorily.

Backs away slowly

Minutes into December 26 (CET), the Hubble telescope was released. Discovery then backed away from Hubble slowly. Having successfully performed the major objectives of the mission, the astronauts on board used the time remaining to stow away equipment, apart from making preparations for landing.

After orbiting the Earth 119 times and travelling more than 5 million km, Discovery made its way back. It performed a smooth night-time landing, touching down on the runway at the Kennedy Space Center in the U.S. on December 27. Hubble was successfully back in operation, and has been for over two decades since then.

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What do we know about Dr. Abhijit Mukherjee?

Dr. Abhijit Mukherjee, a professor of Geology from IIT- Kharagpur features among the top 100 influential people of 2020 by Time magazine. He is famous worldwide for his research in the field of groundwater exploration.

His team introduced a prediction model based on Artificial Intelligence for detecting arsenic in groundwater in the Gangetic delta. This feat was noted by the Jal Jeevan Mission.

A groundwater-surface water interaction is yet another one of his specializations. This work supplied important data regarding drinking water and food security to the Indian government. Dr. Abhijit Mukherjee has done ample researches on groundwater quantity and scarcity by understanding groundwater storage changes over the Indian subcontinent. This was achieved with advanced computation and Artificial Intelligence techniques.

Another significant role of Dr. Mukherjee is as head of one of South Asia’s first Urban Geo-science projects in Varanasi. He has won the Shanti Swarup Bhatnagar Prize for 2020 in the field of Earth, Atmosphere, Ocean and Planetary Sciences.

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Why is Dr. Jagadish Shukla famous?

Dr. Jagadish Shukla was born in a small village, Mirdha, in Uttar Pradesh. The village had no electricity, not even proper roads. The primary school did not have a building, and Jagadish Shukla had his early classes under a large banyan tree! He could not study science in high school because the schools did not include it.

He went to Banaras Hindu University (BHU) and graduated in Physics, Mathematics and Geology. He did MS in Geophysics and then finished his PhD too. Later he got a ScD (Doctor of Science) in Meteorology from the Massachusetts Institute of Technology (MIT).

He chose a career in the atmospheric sciences and became a professor at George Mason University in the U.S.

Dr. Shukla’s study areas include the Asian monsoon dynamics, deforestation and desertification. Do you know what is desertification? It is when the soil loses its quality due to weather or human activity.

Dr. Shukla helped establish weather and climate research centres in India. He also established research institutions in Brazil and the U.S. He has been with the World Climate Research Programme since its start and founded the Centre for Ocean- Land-Atmosphere Studies, Virginia, U.S.

He has also established the Gandhi College in his village for educating rural students, especially women, and was awarded Padma Shri in 2012.

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What are sunspots of the Sun?

Sunspots are regions on the sun that appear dark. They occur in regions where the magnetic field of sun is strong. The temperature of a sunspot is super hot-something around 6,500 degrees Fahrenheit

The Sun, the centre of our solar system and our closest star, is 4.5 billion years old. This fiery glowing orb of hydrogen and helium sustains life as we know it

Sunspots

Sunspots are regions on the sun appear dark. These parts appear darker as they are cooler when compared to other parts of the sun. They occur in regions where the sun’s magnetic field is highly concentrated or strong.

The centre of the sunspot is dark and this is called the umbra while the outer and lighter ring is called the penumbra. Spots vary in sizes. They could be larger than the Earth, or so tiny that it will be difficult to pick them up in telescopic observation. The sunspots could stay on for months. Most of the sunspots can be seen in pairs or groups but single spots also do occur. When they occur in pairs, they have opposite magnetic polarity.

Why are sunspots cooler

Sunspots form in areas on the sun where the magnetic field is very strong and powerful. These magnetic fields will prevent the heat within the Sun from reaching its surface. Even when we say that the sunspots are cooler, this is just in comparison to the other regions of the Sun. The temperature of a sunspot is super hot something around 6.500 degrees Fahrenheit.

Why do sunspots matter

In most cases, sunspots precede the occurrence of a solar flare. Solar flares are sudden bursts or explosions of energy from the sun’s surface. This occurs when the magnetic field lines near the sunspots reorganise or cross. These solar flares will release huge amounts of radiation into space. The more intense the solar flare, the more intense will be its radiation. This can affect radio communication on Earth. Studying and monitoring the sunspots are required to understand the reason behind the occurrence of solar flares.

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What moons did Galileo discover in 1610?

Many years ago, in 1610, Italian astronomer Galileo Galilei discovered the first moons beyond Earth. Those were the moons of the planet Jupiter, the largest planet in the solar system.

Planet Jupiter has 80 moons. There are many interesting moons orbiting the planet, but the ones of great interest to us on a scientific level are the first four moons discovered called the Galilean satellites. They are lo, Europa, Ganymede, and Callisto. Here we look at the four largest moons of Jupiter.

What is a Moon?

Moons are those celestial bodies that orbit planets and asteroids in the solar system. They are also called natural satellites. The Earth has one moon, whilst the solar system has more than 200 moons. Most of the major planets except Mercury and Venus have moons.

Jupiter and Saturn have the most moons. Four of Jupiter’s moons are named after Galileo Galilei who first discovered them.

And how were the Galilean moons formed? According to scientists, the moons were formed out of the dusty disc left after Jupiter was formed.

lo

The most volcanically active body in the solar system, lo has its surface enveloped by sulfur. Jupiter’s gravity causes “tides” that rise some 100 metres high on lo and lead to the generation of heat for volcanic activity.

Europa

Europa’s surface is covered mostly by water ice. This moon is considered to have twice as much water as Earth.

Ganymede

The largest moon in the solar system, Ganymede is the only moon that has its own internally generated magnetic field. Did you know that this moon is even larger than the planet Mercury?

Callisto

The second largest moon of Jupiter, Callisto’s surface is highly cratered and ancient. This moon is about half rock and half ice.

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When was the last human expedition to the moon?

On December 11, 1972, Apollo 17 achieved lunar landing. The sixth mission in the Apollo program to explore the lunar surface, Apollo 17, for now, is the last human expedition to the moon.

Apollo 11 will forever be remembered as the mission which enabled human beings to set foot on the moon, our natural satellite, for the first time. While the first will always remain the the same cannot be said for what is the last such mission, as future missions might take that place. But for the time being, Apollo 17 remains the last human expedition to the moon.

After the success of Apollo 11 in 1969, there were six more Apollo missions to the moon, five of which were successful. As U.S. President John F. Kennedy’s objective of landing humans on the moon had been achieved, NASA faced funding cuts. Technology and research-based missions weren’t seen as important as the landing itself, forcing NASA to cancel some of the planned missions in 1970. As a result, the Apollo 17 mission of 1972 became the last manned mission to the moon.

Firsts and records

Apollo 17 was a 12-day mission that spanned from December 7-19. Apart from the distinction of being the last human expedition to the moon for now, Apollo 17 also achieved a number of firsts and broke some records. It had the then longest space walk and enabled the collection of the largest lunar samples brought back to Earth. It was the first Apollo mission to be launched at night and allowed a scientist to walk on the moon for the first time.

The scientist in question was Harrison H. Schmitt, a geologist who had been part of the backup crew for Apollo 15. Schmitt was originally scheduled to go on Apollo 18, which was cancelled. The scientific community lobbied for Schmitt’s inclusion in Apollo 17. While Schmitt served as the pilot of the lunar module “Challenger”, Eugene A. Cernan was commander and Ronald E. Evans was the pilot of “America”, the command module.

Following a successful night launch on 7, Apollo 17 achieved lunar orbit insertion on December 10. Then, with Evans orbiting the moon, Cernan and Schmitt flew Challenger and landed on the moon’s surface on December 11, touching down within 200 m of the targeted landing point.

Two primary objectives

Apollo 17’s two primary objectives were to obtain a specific sample and to explore geologically recent, explosive volcanism. The former was achieved as they retrieved the oldest known unshocked (unaltered by meteoric impact) rock from the moon. This sample, called Troctolite 76535, is believed to be at least 4.2 billion years old.

The second objective was met as Schmitt discovered orange soil near Shorty crater. This colour was the result of orange and black volcanic glass that had formed in the type of volcanic eruption that is referred to as “fire fountain” on Earth.

Cernan and Schmitt were on the lunar surface for 75 hours, the longest till now. They clocked 22 hours of extravehicular activity (EVA) with the help of their rover and travelled about 36 km. They went as far as 7.4 km away from the Challenger, close to the limit of what was considered the walk-back distance possible, should the rover have failed. Apart from conducting various experiments, they took over 2,000 photographs and collected 110 kg worth of soil and rock samples from 22 different sites.

Last man on the moon

Following the third and final EVA, the duo televised the unveiling of a plaque with a message, which they left on the moon. On December 14, Cernan took humankind’s final step, to date, off the moon.

After lifting off from the moon, the Challenger was docked with America on December 15. Four days later, on December 19, the Apollo 17 capsule splashed down in the Pacific Ocean at a distance of 6.5 km from the recovery ship, after a mission elapsed time of 301 hours.

For 50 years, Cernan has often been referred to as the last man on the moon. With NASA’s Artemis program aiming to return to the moon and even set up a sustained human presence, it might not be long before the next human being sets foot on the moon.

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Which is the smallest planet in the solar system?

Mercury is the smallest planet in our solar system. Located closest to the Sun, it is also the fastest planet in our solar system, travelling at a speed of nearly 47 kilometres per second. In fact, the closer a planet is to the Sun, the faster it travels. Mercury completes one circle around the Sun in just about 88 Earth-days.

When observed from its surface, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight is as much as seven times brighter. But despite this proximity to the Sun, Mercury is not the hottest planet in our solar system- it is Venus. The reason for this is Venus’ dense atmosphere.

Another interesting aspect of Mercury is that the Sun appears to rise briefly, set, and rise again from some parts of the planet’s surface due to its elliptical and egg-shaped orbit, and sluggish rotation. The same phenomenon happens in reverse during sunset.

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What is Protogalaxy?

A protogalaxy is in simpler words a primeval galaxy. It refers to a galaxy that is undergoing the first generation of star formation. It is also defined as a cloud of gas that is forming into a galaxy. This particular celestial mass would just comprise hydrogen gas trapped in some dark matter prior to the initial stages of star formation. The stars are formed from the smaller clumps of gas in the protogalaxy.

Types of Galaxies

There are two types of galaxies viz. elliptical galaxies and spiral galaxies. The majority of the galaxies that you come across are elliptical galaxies and they are called so because they have an even, ellipsoidal shape. They also are comprised with a greater population of older stars when compared to spiral galaxies.

A spiral galaxy normally has a rotating disc replete with spiral ‘arms. The stellar orbits are circular in shape and they have a flattened disk system. Most spiral galaxies also contain in their centre a mini-elliptical galaxy. Our galaxy, the Milky Way, is a spiral galaxy.

So what determines the shape of a galaxy? The rate of star formation during galactic evolution determines whether it turns out into a spiral or elliptical galaxy. If the star formation is at a slower pace, then it turns into a spiral galaxy.

Milky Way

About 12.5 billion years ago, the Milky Way started to form. Several huge clusters of stars and clumps of gas fused together to form a protogalaxy. This was the building basis of our home!

It then collided with many galaxies, and after a lot of mergers, it acquired its present form.

Recently, scientists discovered a population of millions of stars at the center of our galaxy. Those were the remains of the ancient protogalaxy! These oldest stars that were found in the core area of our galaxy were analysed and the scientists found out that they were part of a protogalaxy.

The diameter of which extended to 18 thousand light-years, and with a mass that was 50-200 million times that of the Sun!

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A black hole in Earth’s backyard?

This new black hole is 1.600 light-years away in the constellation Ophiuchus So far scientists have discovered 20 black holes in the Milky Way. About 100 million more are estimated to be present in our galaxy.

A new black hole has been discovered very near to Earth, closer than any other previously found. Christened Gaia BH1, this dormant blackhole is 1.600 light-years away in the constellation Ophiuchus.

This new black hole is ten times as massive as our sun. To date, scientists have found 20 black holes in the Milky Way galaxy whilst 100 million more are estimated to be present in our galaxy. The newly discovered one is three times closer than the earlier black hole which sat about 3,000 light-years away in the constellation Monoceros.

Since there are more undetected black holes, even this newly discovered one wouldn’t hold its spot of “closest to Earth” for too long.

The discovery was mentioned in a paper in the peer-reviewed Monthly Notices of the Royal Astronomical Society. The black hole was discovered by “Kareem El-Badry, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics and his colleagues.

They found evidence of the existence of this dormant black hole using the data from the European Space Agency’s GAIA (Global Astrometric Interferometer for Astrophysics) spacecraft. After they noticed a star in the constellation Ophiuchus moving in unexpected ways, they understood that it was a result of the gravity of an unknown, massive object. Using the observation from other telescopes, they confirmed that the object causing this was a black hole.

What is a Black Hole

A black hole is a celestial body that has an immensely huge gravitational pull, so huge that nothing escapes it. Not even light can escape i it!

The black hole grows by accumulating matter that falls in it. Black holes are formed at the end of the life of a big star. When a massive star collapses after its nuclear fuel depletes, it will collapse onto itself and become a black hole.

It was in 2019 that an image of a black hole was captured for the first time. It was an international collaboration and the astronomers used the Event Horizon Telescope (EHT), networking eight ground-based radio telescopes.

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What was the Centaur project?

The Centaur upper stage rocket is a family of high-energy rockets that has played a pivotal role in advancing global communications and furthering our knowledge of space. November 27, 1963 is an important day in its history as it marked the first in-flight burn of a liquid hydrogen/ liquid oxygen engine.

When we speak about successful space missions, we generally talk about the results they delivered – the satellites that now orbit the Earth or the probes that gathered invaluable data from other planets. There’s a lot of work and plenty of factors, however, that goes into reaching that point. One of them is the upper stage rocket that boosts satellites into orbit and propels probes into space.

Among upper stage rockets, Centaur is a significant achievement as it has served as America’s workhorse in space and has been involved in many success stories. Used for over 100 unmanned launches, Centaur has expanded the frontiers of space and revolutionised communication.

Where it all began

Centaur’s beginnings predate even the existence of NASA as the U.S. Air Force studied a proposal from General Dynamics/ Astronautics Corp. to develop a new booster stage in 1957. With the space race between the U.S. and the Soviet Union heating up during this period, the idea was to give the country an edge, providing a means of orbiting heavy payloads in a very short time.

In 1958, the year NASA was established, Centaur became an official hardware programme with the Air Force as its assigned development authority. While the heaviest Soviet satellite orbiting the Earth at this time was the 1,360-kg Sputnik III, the U.S. had plans for boosting payloads to up to 3,850 kg. They planned to achieve this using Centaur, which was to have a new propulsion system using liquid hydrogen, mixed with liquid oxygen.

By July 1959, Centaur moved from the jurisdiction of the Department of Defense to NASA. Centaurs planned schedule of testing and operation, however, proved too optimistic, as there were a mountain of problems, failures, and delays to overcome.

Silverstein provides the silver lining

In 1962, American engineer Abe Silverstein put his hand up and convinced NASA that his Lewis Research Center could debug the Centaur and manage its problems. Once the entire responsibility was assigned to Lewis under Silverstein, the Lewis engineers got to work, perfecting the booster, while carrying out complex research and development to ensure Centaurs reliability. The fact that Lewis had been involved in pioneering work on high-energy liquid propellants for rockets helped, as this meant that most engineers working with Centaur were already aware of safely handling the liquid hydrogen/ liquid oxygen cryogenic fuels that it used.

The original Centaur rocket measured 30 feet long and 10 feet in diameter. As it used very cold propellants (liquid oxygen at-297 degrees Fahrenheit and liquid hydrogen at -420 degrees Fahrenheit), its tanks required special construction. A doubled walled bulkhead not only served as a heat barrier, but also separated the two compartments containing liquid hydrogen and liquid oxygen. Made of stainless steel less than 200ths of an inch thick, the tank was extremely thin and light-weight even once pressurised.

Following successful assembly, inspection, and shipping to Cape Canaveral, engineers and technicians perform testing procedures that can last weeks. A special tiger team uses a checklist to go through it all once again in the days leading up to any launch, before putting the rocket into start condition for the flight.

Go Centaur!

On November 27, 1963, one such launch took place. While it only carried a dummy payload that was put into orbit, it was a significant milestone. This was NASA’s first successful launch of the Atlas Centaur, proving the compatibility of the Atlas rocket with the upper stage Centaur. Additionally, it had the first in-flight burn of a liquid hydrogen/liquid oxygen engine, showing that these could be safely fired in space. In the decades that followed, there were many more successes for Centaur and a few mishaps too. Centaur was involved in sending the unmanned Surveyor spacecraft, which collected data on the moon’s surface and paved the way for the Apollo missions. Along with Atlas and Titan boosters, Centaur featured as the upper for probes and flybys to all other planets in our solar system.

It didn’t stop there as Centaur also launched orbiting observatories that help expand our knowledge about the universe, peering at space beyond our solar system. Centaur was also involved in launching various satellites into geosynchronous orbits that have changed the face of communication on our planet. While its name might not be often mentioned along with successful missions, Centaur continues to be a workhorse that serves its purpose.

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Which is the largest planet?

The largest planet in our solar system, Jupiter, is located fifth from the Sun. It is more than two times the size of all the planets in our solar system combined. Jupiter has also been instrumental in our understanding of the universe and our place in it. In 1610, Galileo discovered Jupiter’s four large moons: lo, Europa, Ganymede and Callisto. This confirmed the Copernican view that the Earth was not the centre of the universe as these newly discovered celestial objects were revolving around another planet.

It is estimated that eleven Earths could fit across Jupiter’s equator. To put it in other words, if our planet is the size of a grape, then Jupiter is the size of a basket-ball. It has an iconic Great Red Spot, which is a giant storm that has been active in Jupiter’s atmosphere for hundreds of years. This storm is bigger than the Earth!

Jupiter’s orbit is about 778 million kilometres or 5.2 Astronomical Units (AU) from the Sun (Earth is one AU from the Sun). Jupiter is a gas giant, which lacks an Earth-like atmosphere. Even if it has a solid inner core at all, it would only be about the size of the Earth. Jupiter’s atmosphere contains mainly hydrogen (H) and helium (He) and has more than 75 moons. It rotates about its axis once every 10 hours (a Jovian day), and takes about 12 Earth years to complete one revolution about its orbit around the Sun (a Jovian year).

In the year 1979, NASA’s Voyager mission discovered Jupiter’s faint ring system. We have discovered that all the four giant planets of our solar system have ring systems. Till date, nine spacecraft have visited Jupiter. Of them, only the most recent one landed on Jupiter. Seven of them only flew by this gas giant and the other two just orbited it. Juno, the latest spacecraft, arrived on Jupiter in 2016.

Although it is the biggest planet in our solar system, Jupiter cannot support life as we know it. But we have come to know that some of its moons have oceans beneath their crusts, which could possibly support some form of life.

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Dark Matter: A mystery of the Universe

Dark matter accounts for 27 percent of all matter and energy in the universe. What we see, the regular matter is just 5 percent of the universe. The dark matter can be failed stars or white dwarfs or black holes.

First, there was the Big Bang. For several million years after that, there was nothing – no stars, planets, moons or galaxies. This continued for 150 million years after the great Big Bang. Time went by. The first stars were created. Matter fused, stars clumped together, galaxies collected together. The formation of our planetary system began. To hold the solar system and clusters of galaxies together, we had gravity, our glue. Swiss astronomer Fritz  Zwicky who used the term ‘dark matter first. He coined the term ‘Dunkle Materie’ to denote the invisible matter.

Dark Matter

But in some clusters, the space between the galaxies contains hot gases which cannot be seen using light telescopes. After measuring this gas, the scientists came to the opinion that there is more material involved in these clusters than meets the eye and that they cannot be detected. The undetected matter could amount to some five times the material in the cluster. This invisible matter that cannot be detected is called the ‘dark matter. Dark matter accounts for 27 percent of all matter and energy in the universe. What we see, the regular matter is just 5 percent I of the universe.

It was the Swiss astronomer Fritz Zwicky who used the term ‘dark matter first. He coined the term ‘Dunkle Materie’, which translates to dark matter, to denote the invisible matter. His subject was the Coma galaxy cluster. It should be noted that the speed of revolution of a particular cluster is dependent on the weight and position of the matter in the cluster. When he measured the speed, he found out that the cluster had more mass than it was supposed to meaning there was more matter involved. This was further confirmed by other scientists whose work on other galaxies suggested that they had more mass. The presence of dark matter was thus established.

What makes up Dark Matter

According to scientists, dark matter can be failed stars or white dwarfs or black holes. But these are just suggestions and the dark matter still continues to be a mystery. Scientists have however found ways to indirectly study dark matter. This is done by using gravitational lensing. Studies are still being carried out and we are just unraveling all the secrets of the universe.

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What are dwarf galaxies?

As their name suggests, dwarf galaxies are smaller galaxies. In contrast to a normal galaxy that comprises hundreds of billions of stars, a dwarf galaxy would contain just about a few billion stars. These dwarf galaxies orbit larger galaxies after their formation.

Formation of dwarf galaxies

The dwarf galaxies are created when two galaxies collide, fromed from the material and dark matter coming out of the galaxies that collided.

Following these collisions, while a significant portion of the gas, dust and stars emitted gets reincorporated into the galaxy created after the collision, some can lead to the formation of dwarf galaxies which then orbit around the galaxy. They are also formed by the gravitational forces existing during the creation of these larger galaxies.

Why are dwarf galaxies crucial

Scientists consider the dwarf galaxies critical as they could help gain insight into the early stages of the formation of galaxies and stars. According to scientists, our galaxy has about 14 satellite dwarf galaxies orbiting it.

Studies are being carried out on these dwarf galaxies as it would give us clues regarding the evolution of the galaxies. By studying the motion of the stars in these galaxies, we would also get to know more about dark matter and how it is distributed in the galaxies.

It is difficult to spot dwarf galaxies as they are less bright when compared to larger galaxies. A large number of them can be spotted in galaxy clusters or as a companion to larger galaxies.

Shapes of dwarf galaxies

The dwarf galaxies take several shapes. The dwarf elliptical galaxies are quite similar to normal elliptical galaxies.

Then there are dwarf spheroidal galaxies which are more spherical in shape and smaller when compared to the former.

Then we have the irregular dwarf galaxies. They do not have a distinct structure and are rich in gas.

One of the closest dwarf galaxies to the Milky Way is the Sagittarius Dwarf Spheroidal Galaxy.

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Is a missing moon responsible for Saturn’s rings and tilt?

Now known to host at least 83 moons, researchers propose that Saturn at one point must have had at least one more satellite, which they call Chrysalis

While all four gas giants – Jupiter, Saturn, Uranus, and Neptune – have rings, Saturn is the most popular ringed-planet. Swirling around Saturn’s equator, these rings indicate clearly that the planet is spinning at a tilt relative to the plane in which it orbits the sun.

For a long time, astronomers have suspected that this tilt is the result of Saturn’s interactions with neighbouring Neptune. A new modelling study by astronomers at Massachusetts Institute of Technology (MIT). however, suggests that while the two planets may have been in sync before, Saturn has since escaped Neptune’s pull.

Call it Chrysalis

In a study appearing in Science in September, the MIT team

posits that a missing moon might be responsible for this planetary realignment. Now known to host at least 83 moons, Saturn at one point must have had at least one more satellite that the researchers call Chrysalis.

The team estimates that after orbiting Saturn for several billion years, Chrysalis became unstable about 160 million years ago, coming too close to Saturn in the process. As the proposed satellite was long dormant before suddenly becoming active – just like a butterfly’s chrysalis – the researchers gave it the name Chrysalis.

The resulting encounter pulled the satellite apart and the loss of the moon was enough for Saturn to escape

Neptune’s grasp and leave it with its current tilt. Additionally, the researchers suggest that while most of Chrysalis’ shattered body may have impacted Saturn, a fraction of its fragments could have remained suspended in orbit. These could then have broken into small icy chunks to form the planet’s standout rings.

Explains two mysteries

The missing moon hypothesis, the researchers believe, could thus explain two mysteries pertaining to Saturn’s system. While one of these is Saturn’s present-day tilt, the other one is the age of its rings.

The rings are estimated to be about 100 million years old. very much younger than the planet itself. If the rings were indeed formed from fragments of Chrysalis, then the story fits perfectly.

Cassini’s inputs

The team of researchers arrived at this hypothesis by modelling the interior of Saturn. They identified a distribution of mass that matched the gravitational field that was observed by the Cassini spacecraft in its final phases. What they found indicated that Saturn is no longer in sync with Neptune, paving the way for researching various hypotheses, before arriving at their final result. The lead author of the study says that it is “a pretty good story, but like any other result, it will have to be examined by others”.

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How did Japan’s Hayabusa spacecraft collect samples from an asteroid?

Scientists study meteorites for clues about the origin of Earth and the solar system because most meteorites are bits of asteroids that have fallen to Earth, and asteroids are believed to be leftover material from the time the solar system formed.

In 2005, for the first time ever, scientists scooped up rock samples directly from an asteroid using a spacecraft built especially for that purpose. The name of the spacecraft was Hayabusa. It was a robotic spacecraft developed by the Japan Space Exploration Agency (JAXA).

Hayabusa (Japanese for falcon’) was launched on May 9, 2003, and arrived in the vicinity of the asteroid Itokawa in mid-September 2005. In November 2005, it landed on the asteroid and collected samples in the form of tiny grains of rock which it brought back to Earth on June 13, 2010. Hayabusa was the first spacecraft to land and take off from an asteroid.

In December 2014, Japan launched another spacecraft Hayabusa 2 to study the near-Earth asteroid Ryugu and to bring back samples of rock not only from its surface but also from deeper below the surface. Hayabusa 2 reached Ryugu in June 2018.

In September 2018, the spacecraft landed two rovers on the asteroid. They were the first rovers ever to move on an asteroid. They moved with a hopping movement instead of rolling around on wheels. The rovers are designed to take pictures of the landscape and measure the temperatures on the asteroid.

Hayabusa 2 left the asteroid in November-December 2019 and delivered a small capsule that contained the rock and dust samples when it was 220,000 km from the Earth’s atmosphere. The capsule safely landed in the South Australian outback in December 2020.

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Is Earth the only planet that supports life?

Discovery about an Earth-like planet orbiting an M dwarf could imply that planets orbiting the most common star may be uninhabitable.

Is Earth the only planet that supports life? This is one of the many questions for which we don’t have an answer yet. In a universe filled with countless stars and innumerable planets, our quest for life on a planet other than our own continues.

A new discovery could serve as a signpost and maybe even dramatically narrow our search for life on other planets. The discovery, explained in the Astrophysical Journal Letters in October by researchers from the University of California – Riverside, reveals that an Earth-like planet orbiting an M dwarf appears to have no atmosphere at all.

Most common type of star M dwarfs or red dwarfs are the most common type of star in the universe. This discovery could therefore imply that a large number of planets orbiting these stars may also lack atmospheres, and will therefore likely not support life.

The planet named GJ 1252b is slightly larger than our Earth, but is much closer to its star, an M dwarf, than the Earth is to the sun. On a single day on Earth, this planet orbits its star twice.

In order to find out if this planet lacks an atmosphere, astronomers measured infrared radiation from the planet as its light was during a secondary eclipse. In a secondary eclipse, the planet passes behind the star, and hence the planet’s light along with the light reflected from its star are blocked.

Scorching temperatures

The radiation revealed the planet’s daytime temperatures to be of the order of 2,242 degrees Fahrenheit. This, along with assumed low surface pressure, led the astronomers to believe that GJ 1252b lacks an atmosphere.

The researchers concluded that the planet will not be able to hold on to an atmosphere, even if it had tremendous amounts of carbon dioxide, which traps heat. Even if an atmosphere builds up initially, it would taper off and erode away eventually.

With M dwarf stars having more flares, the likelihood of planets surrounding them closely holding onto their atmospheres goes down further. The lack of atmosphere means that life as we know it is unlikely to flourish.

In Earth’s  solar neighbourhood, there are about 5,000 stars and most of them are M dwarfs. If planets surrounding them can be ruled -out entirely in the search for life based on this discovery, that would leave roughly around 1,000 stars similar to the sun that could be habitable.

For now, however, these can’t be ruled out entirely. Nor can we rule out the possibility of a planet far enough away from an M dwarf star such that it retains its atmosphere. We need more research and results as we continue to embark on our search for life elsewhere.

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What are brown dwarfs?

Brown dwarfs are also known as failed stars. Why? Find out

Brown dwarfs are celestial objects that are too large to be called planets and too small to be called stars. They have. a mass less than 0.075 that of the sun, which is around 75 times the mass of Jupiter. Like stars, brown dwarfs are believed to form from a collapsing cloud of gas and dust. But as the cloud collapses, it does not form an object dense enough at its core to trigger a nuclear fusion. In the case of a star, hydrogen is converted into helium by nuclear fusion. This is what fuels a star and causes it to shine. Brown dwarfs, on the other hand, are not massive enough to ignite fusion. Hence, they are also called ‘failed stars’.

Dimmer and cooler than stars, brown dwarfs are elusive and hard to find. Infrared sky surveys and other techniques have, however, helped scientists detect hundreds of them.

They are believed to be as common as stars in the Universe. Some of them are companions to stars and many are isolated objects.

First discovered in 1995, brown dwarfs were hypothesized in 1963 by American astronomer Shiv Kumar. Despite their name, brown dwarfs are not brown. They appear from deep red to magenta, depending on their temperature.

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Voyager 1’s tryst with Jupiter and Saturn

On November 6, 1980, Voyager 1 snapped a picture of Saturn while still 8 million km away from it. Scientists discovered a 15th moon orbiting Saturn from the photo the following day. In a year in which it has completed 45 years of operation,

You must be aware that the twin Voyager probes are now travelling in interstellar space, 45 years since their launch. Before they got there, however, they visited the gas giants in our solar system, gleaning a wealth of information from the flybys. While Voyager 2 flew by all four gas giants – Jupiter, Saturn, Uranus, and Neptune, – Voyager 1 focussed on Jupiter and Saturn.

Even though Voyager 1 is the first spacecraft to travel beyond the solar system and reach interstellar space, it wasn’t the first of the probes to be launched. Launched on September 5, 1977-two weeks after Voyager 2 – Voyager 1, however, was the first to race to Jupiter and Saturn.

Gravitational slingshots

The Voyager missions were planned in such a way that they could maximise a special alignment of the outer planets that happens only once in 176 years. This alignment aided the spacecraft to efficiently use their limited fuel as they moved like a slingshot from one planet to another using gravitational assist.

All the successes that Voyager 1 has achieved might have come to nothing right on the day of the launch. Its rocket came within 3.5 seconds of running out of fuel, meaning Voyager 1 wouldn’t have even got off the ground.

Jupiter flyby

Once it did, however, it raced past its twin, going beyond the asteroid belt before Voyager 2 did. And in April 1978, Voyager 1 beamed back the first pictures of Jupiter back to Earth. By March 1979, it had spotted a thin ring around the giant planet. Apart from sending back detailed photographs of Jupiters Galilean moons (lo, Europa, Ganymede, and Castillo), Voyager 1 also found two new moons – Thebe and Metis.

Voyager 1 collected plenty of data and also made some interesting discoveries about Jupiter’s satellites. Following its closest approach to Jupiter on March 5, 1979, when it came within 2,80,000 km, it headed over to Saturn, a journey that took it just a little over a year.

Just like how its visit to Jupiter had a lot of findings, so it was with Saturn as the ringed planet revealed many of its secrets. As it flew ever closer to Saturn in October-November 1980, Voyager 1 spotted a number of moons, observed its rings and already known moons, and collected data that had scientists digging for decades.

Programmed searches

One of the moons that Voyager 1 spotted was Atlas, the 15th moon orbiting Saturn. In a photograph taken by the spacecraft on November 6 when it was still 8 million km away, the moon was visible near the bottom of the picture.

The first of several programmed searches for new satellites of Saturn thus had success right away as the Voyager imaging team scientists discovered the moon on November 7. An inner moon of Saturn, orbiting around the outer edge of Saturn’s A ring, Atlas takes 14.4 hours to complete its trip around the planet.

Unique perspective

Following its closest approach of Saturn on November 12, Voyager 1 looked back on Saturn four days later on November 16, to observe Saturn and its rings from its unique vantage point. With its primary mission concluded following the Saturn encounter, the focus moved to tracking the spacecraft as it headed to interstellar space.

Having recognised that the Voyagers would eventually make it to interstellar space, NASA had placed Golden Records on board the spacecraft. Designed to carry images, music, and voices from Earth out into the cosmos, the Golden Records have spoken greetings in over 50 languages.

Voyager 1 became the first spacecraft to go beyond the solar system and reach interstellar space on August 25, 2012. At that point, Voyager 1 was over 18 billion km away from the sun. Over a decade later, it has travelled even farther and is now over 23 billion km away from the sun. Voyager 1 has enough fuel to supply power to its instruments until at least 2025, after which it will likely stop collecting scientific data.

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What are the secrets of Enceladus moon?

Discovered on August 28, 1789, Enceladus is a natural satellite of Saturn. This moon, which remained in relative obscurity for nearly 200 years, is now one of the most scientifically interesting destinations in our solar system.

The possibility of worlds other than our own Earth where life could exist has enthralled us for a long time. Often seen in the realm of science fiction, we might be inching ever so closer to it in reality as scientists have identified a handful of worlds that have some of the ingredients needed for life. One of them is Enceladus, an icy moon that is the brightest in the solar system.

Enceladus was discovered on August 28, 1789 by British astronomer William Herschel, more popular for discovering the planet Uranus. Little is known about how William went about it and made his discovery.

A dwarf named after a giant

What we do know, however, is that it was William’s son, John Herschel, who gave the moon its name Enceladus, after the giant Enceladus of Greek mythology. In his 1847 publication Results of Astronomical Observation made at the Cape of Good Hope, John suggested names for the first seven moons of Saturn that had been discovered, including Enceladus. He picked these particular names as Saturn, known in Greek mythology as Cronus, was the leader of the Titans.

For nearly two centuries, very little was known about Enceladus. That changed in the 1980s, when the U.S. spacecrafts Voyager 1 and Voyager 2 flew by the moon, capturing images. The pictures indicated that the icy surface of this small moon is very smooth in some places and bright white all over.

Enceladus, in fact, is the most reflective body in the solar system. Scientists, however, didn’t know why this was the case for a few more decades. Enceladus reflective capability implies that it reflects almost all the sunlight that strikes it, leading to extremely cold surface temperatures, of the order of -200 degree Celsius.

E ring and tiger stripes

Shortly after NASA’s Cassini spacecraft began studying Saturn’s system in 2004, Enceladus started revealing its secrets. By spending over a decade in the vicinity of the small moon, including flybys as close as 50 km, Cassini was able to unearth a wealth of information about Enceladus.

Cassini discovered that icy water particles and gas gush from the moon’s surface at about 400 metres per second. These continuous eruptions create a halo of fine dust around the moon, which supplies material for Saturn’s E ring. While a small fraction of this remains in the ring, the remaining falls like snow back onto the moon’s surface, thereby making it bright white. Scientists informally call the warm fractures on Enceladus’ crust from which the water jets come from as “tiger stripes”.

By measuring the moon’s slight wobble as it orbits Saturn and from gravity measurements based on the Doppler effect, scientists were able to determine that these jets were being supplied by a global ocean inside the moon. As this ocean supplies the jet, which in turn produces Saturn’s E ring, it follows that studying material from the E ring is akin to studying Enceladus’ ocean.

While the E ring is mostly made of ice droplets, there is also the presence of nanograins of silica that can be generated only where liquid water and rock interact at temperatures above 90 degrees Celsius. Along with other evidence that has been gathered, this suggests the existence of hydrothermal vents deep beneath this moon’s shell, similar to those on the Earth’s ocean floor.

Orbital resonance

Enceladus takes 33 hours for its trip around Saturn, which is nearly half of the time taken by the more distant moon Dione. Enceladus is thus trapped in an orbital resonance with Dione, whose gravity stretches Enceladus’ orbit into an elliptical shape. This means that Enceladus is sometimes closer to Saturn and at other times farther leading to tidal heating within the moon.

Running just over 500 km across, Enceladus is small enough to fit within the Indian State of Maharashtra, which runs around 700 km north-south and 800 km east-west. What it lacks in size it more than makes up for in stature, as Enceladus has a global ocean, unique chemistry, and internal heat. All this means that even though we still have plenty of data about the moon to pore over, explorers will eventually plan a return to Enceladus to learn more of its secrets.

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Who is the first Latin American to fly into space?

Arnaldo Tamayo Méndez, (born Jan. 29, 1942, Guantánamo, Cuba), Cuban pilot and cosmonaut, the first Latin American, the first person of African descent, and the first Cuban to fly in space. After the revolution of 1959, Tamayo Méndez joined the Cuban air force as a pilot.

Born in 1942, Mendez makes no mention of his father in his book Un cubano en el cosmos (A Cuban in the cosmos). As he lost his mother to tuberculosis while just eight months old, he grew up as a poor orphan in Guantanamo.

Limited schooling

He worked as a shoeshine boy, sold vegetables, delivered milk and worked as an apprentice carpenter by the time he reached his teenage years. Even though he had limited opportunities for schooling, he excelled at it in whatever little chance he got.

After joining the Association of Young Rebels during the Cuban Revolution, Mendez made his way to a technical institute. Here, he saw a chance to pursue his dream of flying and he readily enrolled himself into a course for aviation technicians, passing it with flying colours in 1961.

His success at this course gave him the confidence to become a pilot and make his dream a reality. He was then selected to travel to the Soviet Union to further his studies and learn to fly the Soviet MiG – 15 fighter jet. Mandez rose through the ranks in the next 15 years, becoming a captain in the Cuban Air Force by 1978.

Interkosmos programme

During the time Mendez was making his way up the Cuban Air Force, the Soviet Union had designed and formed the Interkosmos space programme (1967) and had the first flight of this programme in 1978. The objective of Interkosmos was to help the Soviet Union’s allies with crewed and unscrewed missions to space.

The search for the first Cuban Cosmonaut began in 1976 and a long list of 600 was shortlisted to two by 1978: Mendez and the other being Jose Lopez Falcon. It could have been purely based on merit, or it might have been an act of propaganda with political motivations, but what we do know is that Mendez was selected to fly aboard the Soyuz 38 mission.

On September 18, 1980, Mendez created history as he flew aboard Soyuz 38 along with Soviet cosmonaut Yuri Romanenko. On that same day, they docked at the Salyut 6 space station, and Mendez met Soviet cosmonauts Leonid Popov and Valery Ryumin as the hatch opened and was sealed.

Over the next seven days, Mendez completed 124 orbits around the Earth, conducting a number of experiments on science and health. There were a total of nine experiments, including those that studied stress, blood circulation, immunity, balance, and the growth of a single crystal of sucrose in weightlessness.

Instant fame

Mendez and Romanenko landed back on Earth on September 26 and the former was lauded by both the Cubans and the Soviets Mendez became an instant national hero and was honoured with the Hero of the Republic of Cuba medal, and received The Order of Lenin from the Soviets, among many other recognitions.

Mendez, who is now an 80-year-old, rose to the position of brigadier general following his space flight. He spent many years leading the education efforts of the Cuban army. Cuba’s Museum of the Revolution in Havana is home to the space suit that Mendez used for his historic Voyage.

The Interkosmos programme successfully flew many non-Soviets, including India’s Rakesh Sharma and astronauts from Britain, Japan, France, and Vietnam, among many other countries. Mendez’s flight not only made him the first Cuban cosmonaut, but also the first with African heritage to make it to space.

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What is Avatar?

AVATAR is an acronym for “Aerobic Vehicle for Hypersonic Aerospace Transportation”.

It is a single stage reusable space plane which is capable of horizontal take-off and landing. It is an unmanned spacecraft. DRDO is working on it. This can make satellite launches much cheaper as they can take off from conventional airfields. AVATAR’s liquid air cycle engine collects air on the way up, liquefies it, separates oxygen and stores it on board for flight beyond the atmosphere. AVATAR was first announced in May 1998 at the Aero India 98 exhibition held at Bangalore.

AVATAR was a follow up on the ‘Hyperplane’, a dream project of Dr. Kalam in the 1980s. The Hyperplane projects failed due to their immense weight. AVATAR weighs only 25 tonnes. And 60 per cent of it is liquid hydrogen fuel. It can launch satellites weighing one tonne!

The AVATAR design has been patented in India. Applications for registration of the design have been filed in patent offices in the US, Germany, Russia and China.

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What is small satellite launch vehicle?

The Indian Space Research Organisation has been successful at developing space launch vehicles, building satellites, and launching them. But the space agency faced a glitch recently on the maiden journey of its Small Satellite Launch Vehicle (SSLV). Let’s see what an SSLV is.

As the name suggests, an SSLV is a small satellite launch vehicle capable of launching lightweight satellites. The ISRO’s SSLV is 34 metres tall, weighs 110 tonnes, and is equipped to launch satellites weighing between 10 kg and 500 kg to low earth orbit (LEO), that is up to 500 km from Earth. Such lightweight satellites are also called mini, micro, or nano satellites.

The SSLV has been developed to cater to the emerging market for the launch of small satellites into Earth’s low orbits by developing countries, students, and others. The SSLV is the third offering of the ISRO after the Polar Satellite Launch vehicle (PSV) and the Geosynchronous Satellite Launch Vehicle (GSLV). The key features of the SSLV are low cost, flexibility in accommodating madtiple small satellites, possibility of multiple drop-offs launch-on-demand feasibility, and minimal launch infrastructure requirement On its maiden demonstration flight on

August 7, the SSLV carried an earth observation satellite (LOS-02), and a cube satellite developed by students, named AzandiSAY. The rocket was supposed to place the payloads into the desired 356 km circular orbit. But the satellites were instead placed in an elliptical orbit. It was said the rocket deviated from its path and placed the satellites into 356/76 km low earth orbit due to malfunctioning of a sensor. “As the 76 km elliptical orbit was the lowermost point and closer to the surface of the Earth the satellites placed in such an orbit will not stay for long due to the atmosphere and will come down. The (two satellites) have already come down from that orbit and are no longer usable according to ISRO Chairman S. Somanath.

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India gets world’s first liquid-mirror telescope

India, Belgium, Canada, Poland and Uzbekistan, have collaborated to build the International Liquid Mirror Telescope (ILMT), India’s first liquid mirror telescope and the largest in Asia. It is the world’s first liquid-mirror telescope to be solely set up for astronomy and the only one of its kind to be operational anywhere in the world.

Located at Devasthal Observatory, Aryabhatta Research Institute of Observational Sciences (ARIES) in Nainital, Uttarakhand, the ILMT will observe asteroids, supernovae, space debris and other celestial bodies from an altitude of 2,450 metres.

Most telescopes use glass mirrors, but ILMT’s mirror is made from a thin layer of liquid mercury that floats on 10 microns of compressed air and rotates every eight seconds. The rotation causes the liquid mercury to form a parabolic shape like a contact lens, allowing the telescope to focus light from deep space. The ILMT is fixed in a single position, so it only observes one strip of the night sky as the Earth rotates below it.

ILMT is the third telescope facility to come up at Devasthal, one of the best sites for astronomical observations, and will commence operations in October 2022.

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HAVE YOU EVER WONDERED WHAT THE RESTROOM SCENARIO IN SPACE IS LIKE?

On May 5, 1961, barely three weeks after Soviet cosmonaut Yuri Gagarin’s historic orbit of the Earth, NASA astronaut Alan Shepard waited, strapped into the Freedom 7 spacecraft. He would become the first American in space. What NASA officials hadn’t anticipated was that Shepard would have to endure five hours of delay cocooned in his shiny silver spacesuit before his 15-minute orbit.

“Man, I got to pee,” he frantically radioed launch control. Allowing Shepard to urinate in his suit would destroy the medical sensors he was wired with, but eventually launch control had no option but to let him go. Shepard had to suffer the discomfort of a wet suit till the cooling system inside evaporated the liquid.

Early efforts

NASA hadn’t solved the problem entirely even in 1963 when Gordon Cooper blasted off on the last Project Mercury flight. There was a urine collection device inside the suit, but the urine leaked out of the bag and the droplets seeped into the electronics, leading to a systems failure towards the end of the mission.

If wayward pee was a problem, think of what its twin, poop, could do in the cramped quarters of a spacecraft!

The Gemini project was launched to prepare men for the Apollo moon mission. In 1965, Jim Lovell and Frank Borman spent 14 days flying in Gemini 7, the longest manned mission at the time. They had to poop into a cylindrical plastic bag and add a substance to kill the bacteria and odours. Though the pee could be sent out directly into space through a valve-operated hose, the poo bags had to be stored in the craft till they landed.

By the time the Apollo missions came around, the system hadn’t improved much. The Moon men’s toilet ordeal lasted 45 minutes to an hour. They had to undress completely in a corner of the spacecraft and stick a faecal collection bag to their bottom. Low gravity meant that the poop wouldn’t fall down. The astronauts had to manually help it along with a finger cot, a glove-like covering for a single finger. They also had to knead a germicide into it to prevent the growth of gas-forming bacteria that could cause the bags to explode.

Hit and miss

Accidents did happen. Houston once heard the commander of the 1969 Apollo 10 mission Tom Stafford say, “Give me a napkin quick. There’s a turd floating through the air!”

On the first Space Shuttle mission in 1981, astronauts had to unclog smelly blocked toilets. Frozen urine ejected from the Russian Mir space station, damaged the station’s solar panels over time, reducing their effectiveness by around 40%.

Today, on the International Space Station (ISS), each astronaut is given his or her own funnel for peeing. It attaches to a hose. Urine is sent through a filtration system and recycled into drinking water. There is a proper sit down toilet for more serious business. The waste is sucked into a canister, which is stored and later shot back towards Earth along with other trash, where it burns up in the atmosphere.

Did you know?

Astronauts go through ‘positional training’ on Earth to perfect their aim since the toilet on the ISS has a narrow opening. The mock toilet has a camera at the bottom. Astronauts don’t actually go, but watch a video screen in front of them to check that their alignment is spot on. The toilet costs millions of dollars, so missing the target is not an option.

During a spacewalk or an EVA (extravehicular activity), astronauts wear a maximum absorbency garment, which is essentially a large diaper.

NASA’S 2020 Lunar Loo Challenge, which invited designs from the public for compact toilets that would work well in both microgravity and lunar gravity received tremendous response. The Artemis program plans to land a man and the first woman on the Moon by 2024.

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WHERE SHOULD A ROCKET LAUNCHING SITE BE LOCATED?

Many factors are taken into account while choosing a location for a site from where spacecraft are launched. Firstly, the launch site should be at a remote location as far away as possible from populated areas to reduce the chances of human fatalities on the ground in case of a rocket disaster. It is preferable if it is located next to a major water body such as a sea so that parts shed by flying rockets can fall into the open ???an.

The site should be accessible by land, air, and sea to avoid unnecessary transportation costs and delays. Scientists also prefer a site that has pleasant, mild weather conditions.

Launch sites are usually located near the Equator. Earth rotates from west to east. The surface velocity of the rotation is maximum (about 1600 km/hour) at the Equator. A rocket launched in the easterly direction from a site close to the Equator benefits greatly from the natural boost provided by the surface velocity of Earth’s rotation. This cuts down the cost of rockets used to launch satellites that are destined for the geo-stationary orbit, which runs parallel to the Equator. Most launch sites such as the Guiana Space Centre in French Guiana; Cape Canaveral in the U.S.: Sriharikota in Andhra Pradesh; and Thumba in Kerala – are located near the Equator.

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WHY ARE JUPITER’S RINGS NOT LIKE THOSE OF SATURN?

If we talk about ringed planets, more often than not every one of us will be talking about Saturn. This, despite the fact that all four giants in our solar system Jupiter, Saturn, Uranus, and Neptune – in fact have rings.

This is likely because Saturn has spectacular rings. While the rings of Jupiter and Neptune are flimsy and difficult to view with stargazing instruments traditionally used, the rings of Uranus aren’t as large as that of Saturn’s.

As Jupiter is bigger than Saturn, it ought to have rings that are larger and more spectacular than that of its neighbour. As this isn’t the case, scientists from UC Riverside decided to investigate it further. Their results were accepted by the Planetary Science journal and are available online.

Dynamic simulation

A dynamic computer simulation was run to try and understand the reason why Jupiter’s rings look the way they do. The simulation accounted for Jupiter’s orbit, the orbits of Jupiter’s four main moons, and information regarding the time it takes for rings to form.

The rings of Saturn are largely made of ice, some of which may have come from comets also largely made of ice. When moons are massive, their gravity can either clear the ice out of the planet’s orbit, or change the ice’s orbit such that it collides with the moons.

Massive moons

The Galilean moons of Jupiter Ganymede, Callisto, lo, and Europa- are all large moons. Ganymede, in fact, is the largest moon in our solar system. The four main massive moons of Jupiter would thus destroy any large rings that might form around the planet. This also means that Jupiter is unlikely to have had large. spectacular rings at any time in the past as well.

Ring systems, apart from being beautiful, help us understand the history of a planet. They offer evidence of collisions with moons or comets, indicating the type of event that might have led to their formation. The researchers next plan to use the simulations to study the rings of Uranus to find out what the lifetime of those rings might be.

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WHAT IS THE JAMES WEBB SPACE TELESCOPE?

The James Webb Space Telescope is an infrared observatory orbiting the Sun about 1 million miles from Earth to find the first galaxies that formed in the early universe and to see stars forming planetary systems

The James Webb Space Telescope took 30 years and $10 billion to build, has flown over 1.5 million kilometres away from Earth, and now, we can finally see the first glimpse of its power with a collection of images.

NASA has promised the deepest image of our universe that has ever been taken, and these first sets of images are only the first step in a long job of expanding our view of the universe.

When scientists planned and designed the Hubble Space Telescope, the most groundbreaking astronomical observatory of its era, there were many things about the universe they didn’t know. One of these unknowns was that stars and galaxies existed already a few hundred million years after the Big Bang, Mark McCaughrean, senior advisor for science and exploration at the European Space Agency (ESA).

The technology has come a long way since Hubble’s early years, and the James Webb Space Telescope project has been pushing it further along the way.

“The detectors on JWST have 2000 by 2000 pixels. And we have lots of them,” McCaughrean said. “We have many more infrared pixels [on JWST] than Hubble had optical pixels when it was launched.”

So what exactly will all those pixels (in combination with all the other aspects of the mission that make it so ground-breaking) enable James Webb Space Telescope to do?

The James Webb Space Telescope’s giant mirror will feed the light of stars and galaxies into four cutting edge instruments designed not only to take images, but also to analyze the chemical composition of the near and distant universe. This is done with a technique known as spectroscopy, which looks at how matter in the universe absorbs light. As different chemical elements absorb light at different wavelengths, astronomers will be able to reconstruct what stars, nebulas, galaxies and planets within James Webb’s Space Telescope’s sight are made of.

“The James Webb Space Telescope instruments are a factor 10 to 100 [times] better than anything previously available,” Randy Kimble, JWST project scientist for integration, test and commissioning at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, told Space.com. “In some of those mid-infrared wavelengths, there’s probably an advantage of 1,000 for some kinds of observations.”

These improvements in the resolution of infrared imaging are critical for imaging the furthest reaches of the universe. Where the Hubble Space Telescope, or the recently retired infrared telescope Spitzer, could provide only a rough estimate of an ancient galaxy’s age and chemical composition, Webb will deliver with precision, added Kimble, who previously worked on instruments for the Hubble Space Telescope, including the Wide Field Camera 3, Hubble’s most advanced instrument, which was installed during the final servicing mission in 2009.

Credit : Wikipedia

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WHICH STAR BECAME THE FIRST STAR OTHER THAN OUR SUN TO BE PHOTOGRAPHED?

Vega became the first star other than our sun to be photographed. Visible in the summer sky of the northern hemisphere, Vega is a bright star located about 25 light years from our Earth. On July 16-17, 1850, The days when we could look up to see star-studded skies feel like they are numbered. Especially in cities, as the light pollution makes it impossible for us to enjoy the celestial show. Some stars, however, shine bright enough such that they can be seen even on a moonlit night or from light-polluted cities.

Vega is one such star visible in the summer sky of the northern hemisphere. The brightest star in the constellation Lyra, it is also known as Alpha Lyrae. The fifth-brightest star visible from Earth, it is also among the closest of all bright stars at about 25 light years away.

The Summer Triangle

Along with two other stars – the distant Deneb and the fast-spinning Altair-the blue-white Vega forms an asterism known as the Summer Triangle. These three stars are usually the first to light up the eastern half of the sky after sunset.

Beginning around June and until the end of the year the Summer Triangle pattern can be discerned in the evening every day. Vega, which sinks below the horizon for just seven hours each day, can actually be seen on any day of the year. At mid-northern latitudes on midsummer nights, Vega is usually directly overhead.

The blue-white light of Vega is so bright that it has been observed through the centuries. Be it the Hindus, Chinese, or the Polynesians, the star features prominently in many ancient cultures. Its name, meanwhile, comes from the Arabic word wagi, which means “falling” or “swooping”

First to be photographed

The brightness has meant that Vega has remained relevant in modern times as well, notching up a number of firsts. The first of those firsts came in 1850, when Vega became the first star to be photographed, other than our sun.

On July 16-17, 1850, a 15-inch (38 cm) refractor at the Harvard College Observatory was employed to capture it. Harvard’s first astronomer, William Cranch Bond, had been dabbling with celestial photography at the behest of John Adams Whipple, an American inventor and photographer. Using the daguerreotype process, the duo achieved a 90-second exposure of Vega that yielded the first photograph of a star other than our own. Bond and Whipple, in fact, kept at it and their daguerreotype of the moon the next year created quite a stir at the international exhibition held in London’s Crystal Palace.

Spectrum of a star

A couple of decades later, Vega was again central to another first. Henry Draper, an American doctor and amateur astronomer, was a pioneer in astrophotography. He chose Vega as his subject when he created the first spectrographic image of the star in 1872. Breaking down Vega’s light to reveal the various elements making up the star, Draper had taken the first spectrum of a star other than our sun.

Late in the 1990s, Vega rose to prominence once again after American astronomer Carl Sagan’s novel “Contact” was made into a Hollywood movie. As the movie showed an astronomer discovering a signal appearing to come from Vega while searching for extraterrestrial intelligence, the star captured popular imagination.

Vega’s blue-white light indicates surface temperatures of about 9,400 degree Celsius, much hotter than that of our sun (4,000 degree Celsius). Vega’s diameter is nearly 2.5 times that of the sun, while its mass is also more than twice that of our sun.

Vega is only about 450 million years old, making it a youngster when compared to our sun, which is 4.6 billion years old. Despite Vega being a 10th of the sun’s age, both stars are classified as middle-aged as they are halfway through their respective lives. This means that while our sun will run out of fuel only after another 5 billion years, Vega will burn for only another half-a-billion years.

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WHAT IS SPACE JUNK?

Space junk, or space debris, is any piece of machinery or debris left by humans in space.

It can refer to big objects such as dead satellites that have failed or been left in orbit at the end of their mission. It can also refer to smaller things, like bits of debris or paint flecks that have fallen off a rocket.

Some human-made junk has been left on the Moon, too.

How much space junk is there?

While there are about 2,000 active satellites orbiting Earth at the moment, there are also 3,000 dead ones littering space. What’s more, there are around 34,000 pieces of space junk bigger than 10 centimetres in size and millions of smaller pieces that could nonetheless prove disastrous if they hit something else.

How does space junk get into space?

All space junk is the result of us launching objects from Earth, and it remains in orbit until it re-enters the atmosphere.

Some objects in lower orbits of a few hundred kilometres can return quickly. They often re-enter the atmosphere after a few years and, for the most part, they’ll burn up – so they don’t reach the ground. But debris or satellites left at higher altitudes of 36,000 kilometres – where communications and weather satellites are often placed in geostationary orbits – can continue to circle Earth for hundreds or even thousands of years.

What risks does space junk pose to space exploration?

Fortunately, at the moment, space junk doesn’t pose a huge risk to our exploration efforts. The biggest danger it poses is to other satellites in orbit.

These satellites have to move out of the way of all this incoming space junk to make sure they don’t get hit and potentially damaged or destroyed.

In total, across all satellites, hundreds of collision avoidance manoeuvres are performed every year, including by the International Space Station (ISS), where astronauts live.

Space junk in numbers

2,000 active satellites in Earth’s orbit

3,000 dead satellites in Earth’s orbit

34,000 pieces of space junk larger than 10 centimetres

128 million pieces of space junk larger than 1 millimetre

One in 10,000: risk of collision that will require debris avoidance manoeuvres

25 debris avoidance manoeuvres by the ISS since 1999

How can we clean up space junk?

The United Nations ask that all companies remove their satellites from orbit within 25 years after the end of their mission. This is tricky to enforce, though, because satellites can (and often do) fail. To tackle this problem, several companies around the world have come up with novel solutions.

These include removing dead satellites from orbit and dragging them back into the atmosphere, where they will burn up. Ways we could do this include using a harpoon to grab a satellite, catching it in a huge net, using magnets to grab it, or even firing lasers to heat up the satellite, increasing its atmospheric drag so that it falls out of orbit.

Credit :  Natural History Museam

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CAN PLANTS GROW ON LUNAR SOIL?

Have you ever looked up at our moon and wondered if it was possible to grow plants there? According to a new study published in Communications Biology, the answer is maybe. Success in growing a plant on the moon, it seems, depends on where exactly the planting is done.

The research, performed by a team of two horticulturists and one geologist from the University of Florida, showed for the first time that plants could be grown in lunar soil. The results are an important step towards humanity’s ambitions of making long-term stays on the moon possible.

Third-time lucky

The research has been in the making for a long time. This was the third time that these scientists had applied to NASA over the last 11 years for samples of soil brought back to the Earth by any or all of the six Apollo landing missions. Having been declined on the first two instances, the researchers got their wish this time around.

Probably because NASA themselves are planning longer excursions to our natural satellite, they parted with 12 grams of soil about 18 months ago. This soil was gathered by the crews of Apollos 11, 12, and 17 and were part of just 382 kg of lunar soil and rocks brought back during the Apollo missions.

The researchers chose the thale cress plant, both because of its hardiness and the fact that its genome has been fully sequenced. The planting was done in plastic plates with wells that are usually used to grow cell cultures. There were four wells apiece for each of the three Apollo missions, and they got a gram of soil each. Four more wells were used as a control, with simulated lunar soil prepared using earthly materials.

To their astonishment, researchers noticed that the seeds sprouted after two days. Regardless of whether they were growing in a lunar sample or in the control, they looked the same for the first six days. Differences began to emerge after that as the plants grown in lunar soil showed stress, developed slowly, and ended up being stunted.

Geological age factor

There were also differences within the lunar samples as the Apollo 11 plans grew most poorly, followed by Apollo 12 and then Apollo 17. The researchers concluded that the reason for this has to do with the age of the soil. While the samples brought back by Apollo 11 are older geologically than those brought back by Apollo 12, the samples from Apollo 17 are most recent in geological time.

The results from this research are very important as it helps us develop food sources for future astronauts who might live and operate in deep space for extended durations. Such plant growth research could also unlock innovations in agriculture that might allow us to grow plants under stressful conditions in places where food is scarce here on Earth.

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WHAT IS JUPITER’S IO MOON?

Io or Jupiter I, is the innermost and third-largest of the four Galilean moons of the planet Jupiter. Slightly larger than Earth’s moon, Io is the fourth-largest moon in the Solar System, has the highest density of any moon, the strongest surface gravity of any moon, and the lowest amount of water (by atomic ratio) of any known astronomical object in the Solar System. It was discovered in 1610 by Galileo Galilei and was named after the mythological character Io, a priestess of Hera who became one of Zeus’s lovers.

With over 400 active volcanoes, Io is the most geologically active object in the Solar System.

This extreme geologic activity is the result of tidal heating from friction generated within Io’s interior as it is pulled between Jupiter and the other Galilean moons—Europa, Ganymede and Callisto. Several volcanoes produce plumes of sulfur and sulfur dioxide that climb as high as 500 km (300 mi) above the surface. Io’s surface is also dotted with more than 100 mountains that have been uplifted by extensive compression at the base of Io’s silicate crust. Some of these peaks are taller than Mount Everest, the highest point on Earth’s surface.  Unlike most moons in the outer Solar System, which are mostly composed of water ice, Io is primarily composed of silicate rock surrounding a molten iron or iron sulfide core. Most of Io’s surface is composed of extensive plains with a frosty coating of sulfur and sulfur dioxide.

Io’s volcanism is responsible for many of its unique features. Its volcanic plumes and lava flows produce large surface changes and paint the surface in various subtle shades of yellow, red, white, black, and green, largely due to allotropes and compounds of sulfur. Numerous extensive lava flows, several more than 500 km (300 mi) in length, also mark the surface. The materials produced by this volcanism make up Io’s thin, patchy atmosphere and Jupiter’s extensive magnetosphere. Io’s volcanic ejecta also produce a large plasma torus around Jupiter.

Io played a significant role in the development of astronomy in the 17th and 18th centuries; discovered in January 1610 by Galileo Galilei, along with the other Galilean satellites, this discovery furthered the adoption of the Copernican model of the Solar System, the development of Kepler’s laws of motion, and the first measurement of the speed of light. Viewed from Earth, Io remained just a point of light until the late 19th and early 20th centuries, when it became possible to resolve its large-scale surface features, such as the dark red polar and bright equatorial regions. In 1979, the two Voyager spacecraft revealed Io to be a geologically active world, with numerous volcanic features, large mountains, and a young surface with no obvious impact craters. The Galileo spacecraft performed several close flybys in the 1990s and early 2000s, obtaining data about Io’s interior structure and surface composition. These spacecraft also revealed the relationship between Io and Jupiter’s magnetosphere and the existence of a belt of high-energy radiation centered on Io’s orbit. Io receives about 3,600 rem (36 Sv) of ionizing radiation per day.

Further observations have been made by Cassini–Huygens in 2000, New Horizons in 2007, and Juno since 2017, as well as from Earth-based telescopes and the Hubble Space Telescope.

Credit : Wikipedia 

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WHICH IS THE LARGEST BLOWHOLE?

The Kiama Blowhole is a blowhole in the town of Kiama, New South Wales, Australia. The name ‘Kiama’ has long been translated as “where the sea makes a noise”. It is one of the town’s major tourist attractions. Under certain sea conditions, the blowhole can spray 50 litres of water up to 25 metres (82 ft) in the air, in quantities that thoroughly drench any bystanders. There is a second, less famous blowhole in Kiama, commonly referred to as the “Little Blowhole” by locals. It is much smaller than the other (called the “Big Blowhole”), but due to its narrow shape, it is more reliable than the Big Blowhole, and in the right conditions can be equally spectacular.

The blowhole attracts 900,000 tourists a year. Kiama Blowhole is just a few metres beyond the coastline. The “little blowhole” is located at the Little Blowhole Reserve, Tingira Crescent, Kiama, 2km south of the main blowhole.

The blowhole was formed from basalt lava flows approximately 260 million years ago and was first discovered by local Aboriginals who named it ‘Khanterinte’. The blowhole was first written about by George Bass on 6 December 1797. Bass had captained a crew of six and set out on an open whaleboat to explore the south coast of Australia. He noticed the blowhole after anchoring his boat in a sheltered bay.

Credit: Wikipedia

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What makes Russia a prominent country in space explorations?

Russia has achieved great heights in the field of space technology and space exploration, and its national space agency is known as Roscosmos. These achievements can be traced back to Konstantin Tsiolkovsky, who is known as the father of theoretical astronautics. His works inspired Soviet rocket engineers, such as Sergey Korolyov, Valentin Glushko, and many others to contribute immensely to the Soviet space programme in its early stages, leading to its participation in what is called the ‘Space Race’.

There is a name that one cannot forget in the history of space expeditions – Sputnik-1. In 1957, this satellite was launched by Russian scientists as the first Earth-orbiting artificial satellite. Later, in 1961, Yuri Gagarin made the first human trip into space. This was followed by a number of other Soviet and Russian space explorations, which include the journey of Valentina Tereshkova in 1963 to become the first woman in space. She flew alone in Vostok 6. Russia also holds the record for the first human to have conducted a spacewalk-in 1965, Alexei Leonov exited the space capsule of the mission Voskhod-2 and walked in space.

Can you guess what other records Russia has in this area? They sent the first animal into outer space. Travelling in Sputnik-2 in 1957, a dog named Laika became the first animal to orbit the Earth. In 1966, Luna-9, landed on the Moon, making it the first spacecraft to achieve a survivable landing on a celestial body. In 1968, Zond-5 completed the mission of circumnavigating the Moon with two tortoises and other life forms from Earth. Later, Russia’s Venera-7 became the first spacecraft to land on Venus. Following this achievement, Mars-3 became the first spacecraft to land on Mars in the very next year 1971. During this time, Russia also sent Lunokhod-1, which became the first space exploration rover. Salyut-1 became the world’s first space station, which was yet again a Russian project. As per the 2021 data, Russia had 167 active satellites in space, which is the world’s third-highest count.

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WHAT IS THE DIFFERENCE BETWEEN CONSTELLATIONS AND ASTERISMS?

Constellations are the 88 recognized patterns and groups of stars. These groups and patterns are usually associated with mythology. Today, constellations are not only the groups of stars, but now refers to the entire region of the sky that it takes up.

Asterisms are groups of stars that do not form their own constellations, but instead, are inside of constellations. The Big Dipper is an example of this. The Big Dipper is an asterism inside of the constellation Ursa Major. So I believe that asterisms are smaller than the constellations that they’re in, but not necessarily bigger than all constellations.

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WHAT IS AN ASTERISM?

An asterism is an observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept then the formally defined 88 constellations. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms. For example, the asterism known as the Big Dipper comprises the seven brightest stars in the constellation Ursa Major. Another is the asterism of the Southern Cross, within the constellation of Crux.

Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky.

The patterns of stars seen in asterisms are not necessarily a product of any physical association between the stars, but are rather the result of the particular perspectives of their observations. For example the Summer Triangle is a purely observational physically unrelated group of stars, but the stars of Orion’s Belt are all members of the Orion OB1 association and five of the seven stars of the Big Dipper are members of the Ursa Major Moving Group. Physical associations, such as the Hyades or Pleiades, can be asterisms in their own right and part of other asterism at the same time.

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WHICH IS THE SMALLEST CONSTELLATION?

The smallest constellation is Crux, the Southern Cross. A small group of four bright stars that forms a Latin cross in the southern sky, Crux is visible from latitudes south of 25 degrees north and completely invisible in latitudes above 35 degrees north (in the United States, roughly north of Texas).

Originally it was part of the constellation Centaur, but became its own constellation during the 16th century when it was used as a valuable navigation tool by explorers. Its area is calculated at about 68 square degrees.

Blue-white ? Crucis (Acrux) is the most southerly member of the constellation and, at magnitude 0.8, the brightest. The three other stars of the cross appear clockwise and in order of lessening magnitude: ? Crucis (Mimosa), ? Crucis (Gacrux), and ? Crucis (Imai). ? Crucis (Ginan) also lies within the cross asterism. Many of these brighter stars are members of the Scorpius–Centaurus association, a large but loose group of hot blue-white stars that appear to share common origins and motion across the southern Milky Way.

Crux contains four Cepheid variables, each visible to the naked eye under optimum conditions. Crux also contains the bright and colourful open cluster known as the Jewel Box (NGC 4755) on its eastern border. Nearby to the southeast is a large dark nebula spanning 7° by 5° known as the Coalsack Nebula, portions of which are mapped in the neighbouring constellations of Centaurus and Musca.

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WHICH IS THE LARGEST CONSTELLATION?

Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees, and also the longest at over 100 degrees. Its southern end borders Libra and Centaurus and its northern end borders Cancer. It was included among the 48 constellations listed by the 2nd century astronomer Ptolemy. Commonly represented as a water snake, it straddles the celestial equator.

Despite its size, Hydra contains only one moderately bright star, Alphard, designated Alpha Hydrae. It is an orange giant of magnitude 2.0, 177 light-years from Earth. Its traditional name means “the solitary one”. Beta Hydrae is a blue-white star of magnitude 4.3, 365 light-years from Earth. Gamma Hydrae is a yellow giant of magnitude 3.0, 132 light-years from Earth.

Hydra has one bright binary star, Epsilon Hydrae, which is difficult to split in amateur telescopes; it has a period of 1000 years and is 135 light-years from Earth. The primary is a yellow star of magnitude 3.4 and the secondary is a blue star of magnitude 6.7. However, there are several dimmer double stars and binary stars in Hydra. 27 Hydrae is a triple star with two components visible in binoculars and three visible in small amateur telescopes. The primary is a white star of magnitude 4.8, 244 light-years from Earth. The secondary, a binary star, appears in binoculars at magnitude 7.0 but is composed of a magnitude 7 and a magnitude 11 star; it is 202 light-years from Earth. 54 Hydrae is a binary star 99 light-years from Earth, easily divisible in small amateur telescopes. The primary is a yellow star of magnitude 5.3 and the secondary is a purple star of magnitude 7.4. N Hydrae (N Hya) is a pair of stars of magnitudes 5.8 and 5.9. Struve 1270 (?1270) consists of a pair of stars, magnitudes 6.4 and 7.4.

The other main named star in Hydra is Sigma Hydrae (? Hydrae), which also has the name of Minchir, from the Arabic for snake’s nose. At magnitude 4.54, it is rather dim. The head of the snake corresponds to the ?shlesh? Nakshatra, the lunar zodiacal constellation in Indian astronomy. The name of Nakshatra (Ashlesha) became the proper name of Epsilon Hydrae since 1 June 2018 by IAU.

Hydra is also home to several variable stars. R Hydrae is a Mira variable star 2000 light-years from Earth; it is one of the brightest Mira variables at its maximum of magnitude 3.5. It has a minimum magnitude of 10 and a period of 390 days. V Hydrae is an unusually vivid red variable star 20,000 light-years from Earth. It varies in magnitude from a minimum of 9.0 to a maximum of 6.6. Along with its notable color, V Hydrae is also home to at least two exoplanets. U Hydrae is a semi-regular variable star with a deep red color, 528 light-years from Earth. It has a minimum magnitude of 6.6 and a maximum magnitude of 4.2; its period is 115 days.

Hydra includes GJ 357, an M-type main sequence star located only 31 light-years from the Solar System. This star has three confirmed exoplanets in its orbit, one of which, GJ 357 d, is considered to be a “Super-Earth” within the circumstellar habitable zone.

Credit : Wikipedia 

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HOW MANY CONSTELLATIONS ARE RECOGNIZED BY INTERNATIONAL ASTRONOMICAL UNION?

There are 88 modern constellations recognized by the International Astronomical Union (IAU). The list of the modern constellations was adopted by the IAU in 1922. The constellation boundaries as we know them today were set in the late 1920s. 36 modern constellations lie principally in the northern celestial hemisphere, while 52 are found in the southern sky.

The list of the modern constellations and the abbreviations used for them were produced by American astronomer Henry Norris Russell and approved by the IAU in May 1922. Russell’s list corresponded to the constellations listed in the Revised Harvard Photometry star catalogue, published by Harvard College Observatory in 1908. The constellation boundaries were drawn by Belgian astronomer Eugène Delporte and officially adopted in 1928.

The 88 modern constellations have different origins. Most of them are roughly based on the 48 ancient constellations catalogued by the Greek astronomer Claudius Ptolemy of Alexandria in his Almagest, an ancient astronomical treatise written in the 2nd century CE. These constellations are mostly associated with figures from Greek mythology. They include Andromeda, Cassiopeia, Perseus, Pegasus, Hercules, Orion, Ursa Major, Ursa Minor, Canis Major, Canis Minor, Eridanus, and the 12 zodiac constellations.

However, Ptolemy did not create these constellations. They were already well-known to observers long before his time. Even though they are called Greek constellations, they were not necessarily created by the Greeks. Depictions of some of the ancient constellations or the asterisms they are known for go back to prehistoric times and their creators are unknown.

Fifty of the modern 88 constellations are based on the Greek ones. Only one of Ptolemy’s constellations – Argo Navis – is no longer in use. Once the largest constellation in the sky, Argo Navis represented the ship of Jason and the Argonauts. It was divided into three smaller constellations – Carina, Puppis and Vela – by the French astronomer Nicolas-Louis de Lacaille in the 18th century. The three smaller constellations remain in use.

Credit : Constellation-guide

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WHO WAS CHARLES ROBERT DARWIN?

Charles Robert Darwin was the father of evolution. The English naturalist, biologist and geologist may have devoted his lifetime to science, but he was also a romantic, a doting father and possessed a gentle disposition.

Darwin’s journey to being history’s favorite  biologist, however, had strange twists and turns. He tried to study medicine, but gave it up to pursue theology at Christ College. Cambridge.

But the study of the divine could not contain his ever inquisitive mind. While in college, he devoured journals and books in botany and geology in his free time. He loved gardening and had a special interest in collecting beetles. He learnt physics and geometry with great enthusiasm and noted down his observations diligently.

Darwin took great delight in William Wordsworth and ST Coleridge’s poetry, claiming to have read Wordsworth’s long poem Excursion twice. His favourite work of literature, however, was Paradise Lost by John Milton, which he carried along with him on his first voyage to South America in 1831 as a scientist in training to assist his mentor, botanist, geologist and priest John Henslow.

He nurtured a habit of writing, too. A meticulous diarist, he kept recording daily events, both scientific and personal. For six years of his life – between 40 and 46 years – he even made notes of his illnesses. He wrote about battling insomnia, restlessness, stomach pain, dizziness, rashes and melancholy among other issues.

He married the love of his life, Emma and had ten children with her. “Children are one of life’s greatest joys,” he wrote to a friend. The cover pages of the original manuscript draft of his iconic work, On The Origin of Species by Means of Natural Selection, contain a number of doodles by his children. While many are caricatures of Darwin himself, one depicts a vegetable war – turnips, carrots, eggplant and more engaged in a fierce battle, while another shows a bright green frog, wearing pink shoes on an outing, carrying a blue umbrella. These drawings have been digitized by the American Museum of Natural History.

It took Darwin 20 years to publish his momentous work, On The Origin of Species by Means of Natural Selection. On November 24, 1859, it appeared in bookstores in England. Priced at 15 shillings a copy, all the 1,250 copies were sold out on that very day. The book is considered to be the foundation of evolutionary biology, a revolutionary work that changed the course of science.

What truly kept Darwin going was his unrelenting passion for the natural world: He took in everything with childlike interest. On his first journey to South America, to study the natural world, he was extremely sea-sick. But he religiously collected birds, plants, skeletons, lizards, fossils and small animals, converting the ship into a museum of specimens.

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WHY DOES A SHADOW PASS OVER THE MOON DURING A LUNAR ECLIPSE?

When the Moon passes between Sun and Earth, the lunar shadow is seen as a solar eclipse on Earth. When Earth passes directly between Sun and Moon, its shadow creates a lunar eclipse. Lunar eclipses can happen only when the Moon is opposite the Sun in the sky, a monthly occurrence we know as a full Moon. Lunar eclipses can happen only when the Moon is opposite the Sun in the sky, a monthly occurrence we know as a full Moon. But lunar eclipses do not occur every month because the Moon’s orbit is tilted five degrees from Earth’s orbit around the Sun, so most of the time the Moon passes above or below the shadow. Without the tilt, lunar eclipses would occur every month.

Lunar and solar eclipses occur with about equal frequency. Lunar eclipses are more widely visible because Earth casts a much larger shadow on the Moon during a lunar eclipse than the Moon casts on Earth during a solar eclipse. As a result, you are more likely to see a lunar eclipse than a solar eclipse.

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WHY DOES A COMET HAVE A TAIL?

A comet has two tails. One is a dust tail pushed by light from the sun. Wired Science blogger Rhett Allain uses physics to explain how light can push on matter.

There are two tails because there are two ways the comet can interact with the sun. Everyone thinks about light coming from the sun. However, there is also the solar wind. The solar wind is really just charged particles (like electrons and protons) that escape from the sun due to their high velocities. These charged particles then interact with the ionized gas produced from the comet.

The other tail is due to an interaction with the dust produced by the comet and the light from the sun. Really, it is this interaction that I want to talk about.

Credit : Wired.com

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WHAT IS THE FROZEN PART OF COMETS IS CALLED ?

The nucleus is the solid core of a comet consisting of frozen molecules including water, carbon monoxide, carbon dioxide, methane and ammonia as well as other inorganic and organic molecules — dust. According to ESA the nucleus of a comet is usually around 10 kilometers across or less.

Comets are separated into three distinct parts called the tail, nucleus and the coma which ensures its workability. Comets work in the sense that they tend to be more explicit when they come closer to the source of illumination, the Sun. The tail of a comet is made up of three other parts, the ion tail, the hydrogen envelope, and the dust tail. All these are also vital for the movement of the comet both to and from the sun as indicated below.

The nucleus of a comet is made up of ice, gas, dust, and rocks. It is found right at the center of the head of a comet. The nucleus of a comet is often frozen. The part which is occupied by the gas in the comet’s nucleus is made up of carbon dioxide, the carbon monoxide, ammonia, and methane.

The comet’s area which is made up of the nucleus encompasses between 0.6 to around 6 miles. At times, it is even more than this distance. The nucleus, following this combination of materials, carries the most mass of the comet. The nucleus of a comet is also regarded as one of the darkest objects ever witnessed in the space.

Credit : Earth eclipse

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WHAT IS IT CALLED WHEN A COMET IS CLOSEST TO THE SUN?

Coma. As a comet gets closer to the sun, the ice on the surface of the nucleus begins turning into gas, forming a cloud around the comet known as the coma. According to science website howstuffworks.com the coma is often 1,000 times larger than the nucleus. Outside the coma is a layer of hydrogen gas called a hydrogen halo which extends up to 1010 meters in diameter. The solar wind then blows these gases and dust particles away from the direction of the Sun causing two tails to form. These tails always point away from the Sun as the comet travels around it. One tail is called the ion tail and is made up of gases which have been broken apart into charged molecules and ions by the radiation from the Sun. Since the most common ion, CO+ scatters the blue light better than red light, to observers, this ion tail often appears blue.

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HOW MANY COMETS HAVE BEEN IDENTIFIED SO FAR?

The current number of known comets is: 3,743. Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices. They range from a few miles to tens of miles wide, but as they orbit closer to the Sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet. This material forms a tail that stretches millions of miles.

Comets are cosmic snowballs of frozen gases, rock, and dust that orbit the Sun. When frozen, they are the size of a small town. When a comet’s orbit brings it close to the Sun, it heats up and spews dust and gases into a giant glowing head larger than most planets. The dust and gases form a tail that stretches away from the Sun for millions of miles. There are likely billions of comets orbiting our Sun in the Kuiper Belt and even more distant Oort Cloud.

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WHAT IS THE CONCEPT OF MAN-MADE MOON?

China announced its plan in 2018 to launch an artificial moon to light up the night sky. If the plan clicks, China’s “illumination satellite” would orbit above the city of Chengdu and glow along with the actual Moon, but eight times brighter. The idea of a fake moon is to replace street lamps and lower electricity charges.

The facility, slated for official launch this year, will use powerful magnetic fields inside a 2-foot-diameter (60 centimeters) vacuum chamber to make gravity “disappear.” The scientists were inspired by an earlier experiment that used magnets to levitate a frog.  Scientists plan to use the facility to test technology in prolonged low-gravity environments before it is sent to the moon, where gravity is just one-sixth of its strength on Earth. This will allow them to iron out any costly technical kinks, as well as test whether certain structures will survive on the moon’s surface and assess the viability of a human settlement there.

According to the researchers, the inspiration for the chamber came from Andre Geim, a physicist at the University of Manchester in the U.K. who won the satirical Ig Nobel Prize in 2000 for devising an experiment that made a frog float with a magnet.

The levitation trick used by Geim and now in the artificial-moon chamber comes from an effect called diamagnetic levitation. Atoms are made up of atomic nuclei and tiny electrons that orbit them in little loops of current; these moving currents, in turn, induce tiny magnetic fields. Usually, the randomly oriented magnetic fields of all the atoms in an object, whether they belong to a drop of water or a frog, cancel out, and no material-wide magnetism manifests.

Apply an external magnetic field to those atoms, however, and everything changes: The electrons will modify their motion, producing their own magnetic field to oppose the applied field. If the external magnet is strong enough, the magnetic force of repulsion between it and the field of the atoms will grow powerful enough to overcome gravity and levitate the object — whether it’s an advanced piece of lunar tech or a confused amphibian — into the air.

The tests completed in the chamber will be used to inform China’s lunar exploration program Chang’e, which takes its name from the Chinese goddess of the moon. This initiative includes Chang’e 4, which landed a rover on the far side of the moon in 2019, and Chang’e 5, which retrieved rock samples from the moon’s surface in 2020. China has also declared that it will establish a lunar research station on the moon’s south pole by 2029.

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DOES THE TEMPERATURE OF NEPTUNE CHANGE?

Neptune, the farthest planet in the solar system, takes more than 165 years to complete an orbit around the sun. As Neptune has an axial tilt, it experiences seasons, just like our Earth.

Sensing emitted heat : Neptune’s great distance from the sun and the longer period of revolution, however, implies that its seasons change slowly, lasting over 40 Earth years each. A new research published in April in Planetary Science Journal revealed that the temperatures in Neptune’s atmosphere have fluctuated unexpectedly over the last two decades, even though this period only represents half of a Neptune season.

An international team of researchers that included scientists from Leicester and NASA’s Jet Propulsion Laboratory used observations that effectively sensed heat emitted from Neptune’s atmosphere. They combined two decades worth of thermal infrared images of Neptune from the European Southern Observatory’s Very Large Telescope; Gemini South telescope in Chile; Subaru Telescope, Keck Telescope, and the Gemini North Telescope in Hawaii; and spectra from NASA’s Spitzer Space Telescope.

Cooler than we thought :  Analysing this data allowed the researchers to reveal a complete picture of trends in Neptune’s temperatures like never before, and some of these revelations were unexpected, to say the least. Since the beginning of reliable thermal  imaging of Neptune in 2003, the datasets indicate a decline in Neptune’s thermal brightness, which came as a surprise to the researchers. This means that the globally averaged temperature in Neptune’s atmosphere has come down by almost 8 degrees Celsius from 2003 to 2018, making the planet cooler than what we thought  before.

The data from Neptune’s south pole, however, reveals a different dramatic change. Observations of this region show that Neptune’s polar stratosphere has warmed up by nearly 11 degrees Celsius from 2018 to 2020, reversing the previous cooling trend.

As of now, the causes for these stratospheric temperature changes are unknown and follow-up observations of the temperature will be needed to further assess these findings. Some of those causes might be revealed by the James Webb Space Telescope that is set to observe both Uranus and Neptune later this year.

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What is the longest drive record Perseverance Mas rover has set?

NASA’s Perseverance Mars rover set a new record for the longest drive in a single Martian day, travelling 245.76 metres (806 feet) on the surface of Mars on February 4. The previous record was held by NASA’s Opportunity rover in 2005 (214 metres/702 feet). Perseverance broke a second record, surpassing its own longest AutoNav drive. NASA integrated this function into a rover for the first time. When in AutoNav, the rover drives autonomously by navigating through 3D maps and software that help it avoid obstacles. This feature makes Perseverance faster as compared to when it’s being remotely controlled by NASA personnel; it would only traverse about 200 metres a day which would lengthen the timeline of exploration. Perseverance landed on the red planet a year ago and is on a mission to seek out signs of ancient microbial life. It has collected six samples of Martian rock and atmosphere, over 50GB of science data and has sent back over 100,000 images. It has also snapped two selfies on the Martian surface!

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Where are most meteorites found?

Researchers from Delft University of Technology in The Netherlands have used artificial intelligence to create a treasure map of zones in which to find meteorites hidden in Antarctic ice.

Sixty-two per cent of all meteorites recovered on Earth were found in Antarctica, making this cold continent a hotbed for space research. These meteorites provide a unique view into the origin and evolution of the solar system.

Meteorites have been accumulating in Antarctica for millennia, falling from space and becoming embedded in ice sheets within the continent’s interior. As the glaciers slowly flow, the meteorites are carried with them. If a glacier comes up against a large obstacle, in areas like the Transantarctic Mountains, the ice rises and meteorites are brought to the surface. Dry Antarctic winds gradually erode the ice, exposing the meteorites. As more ice rises to the surface, the process repeats. Given enough time, a significant accumulation of meteorites builds up.

Researchers say that satellite observations of temperature, ice flow rate, surface cover and geometry are good predictors of the location of meteorite rich areas, and expect the “treasure map’ to be 80 per cent accurate. Based on the study, scientists calculate that as many as 300,000 meteorites are out there on the Antarctic landscape.

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WHO STUDIES ROCKS AND MINERALS?

A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, although backgrounds in physics, chemistry, biology, and other sciences are also useful. Field research (field work) is an important component of geology, although many subdisciplines incorporate laboratory and digitalised work.

Geologists work in the energy and mining sectors searching for natural resources such as petroleum, natural gas, precious and base metals. They are also in the forefront of preventing and mitigating damage from natural hazards and disasters such as earthquakes, volcanoes, tsunamis and landslides. Their studies are used to warn the general public of the occurrence of these events. Geologists are also important contributors to climate change discussions.

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WHAT IS FLUORITE?

Fluorite is a very popular mineral, and it naturally occurs in all colors of the spectrum. It is one of the most varied colored minerals in the mineral kingdom, and the colors may be very intense and almost electric. Pure Fluorite is colorless; the color variations are caused by various impurities. Some colors are deeply colored, and are especially pretty in large well-formed crystals, which Fluorite often forms. Sometimes coloring is caused by hydrocarbons, which can be removed from a specimen by heating. Some dealers may apply oil treatment upon amateur Fluorite specimens to enhance luster.

Fluorite has interesting cleavage habits. The perfect cleavage parallel to the octahedral faces can sometimes be peeled off to smooth out a crystal into a perfect octahedron. Many crystals, especially larger ones, have their edges or sections chipped off because of the cleavage.

Fluorite is one of the more famous fluorescent minerals. Many specimens strongly fluoresce, in a great variation of color. In fact, the word “fluorescent” is derived from the mineral Fluorite. The name of the element fluorine is also derived from Fluorite, as Fluorite is by far the most common and well-known fluorine mineral.

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WHY ARE AMETHYSTS PURPLE?

The color in amethyst comes from color centers in the quartz. These are created when trace amounts of iron are irradiated ( from the natural radiation in the rocks).

The purple color in ghost town glass comes from small amounts of manganese in the glass when it has been exposed to ultraviolet light. The manganese was used as a clarifying ingredient in glass from 1860 to 1915. Prior to that, lead was used, and subsequently, selenium is used.

Quartz will commonly contain trace amounts of iron ( in the range of 10’s to 100’s parts per million of iron). Some of this iron sits in sites normally occupied by silicon and some is interstitial (in sites where there is normally not an atom). The iron is usually in the +3 valence state.

Gamma ray radiation can knock an electron from an iron lattice site and deposit the electron in an interstitial iron. This +4 iron absorbs certain wavelengths (357 and 545 nanometers) of light causing the amethyst color. You need to have quartz that contains the right amounts of iron and then is subjected to enough natural radiation to cause the color centers to form.

The color of amethyst has been demonstrated to result from substitution by irradiation of trivalent iron (Fe+3) for silicon in the structure, in the presence of trace elements of large ionic radius, and, to a certain extent, the amethyst color can naturally result from displacement of transition elements even if the iron concentration is low.

Amethyst occurs in primary hues from a light pinkish violet to a deep purple. Amethyst may exhibit one or both secondary hues, red and blue. The best varieties of amethyst can be found in Siberia, Sri Lanka, Brazil and the far East. The ideal grade is called “Deep Siberian” and has a primary purple hue of around 75–80%, with 15–20% blue and (depending on the light source) red secondary hues.

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WHAT ARE VALUABLE MINERALS?

Valuable minerals are either metal or rock that can be processed and converted for economic purposes. Gemstones such as diamonds, rubies, sapphires and emeralds are valuable minerals. Gold and silver are also precious. Palladium is considered more precious than gold and it is very valuable to automotive industries.

Diamond

Diamond is commercially the most popular mineral because of its eminent role in the world of jewelry trading.

 Rubies

Rubies are considered to be the most expensive gemstones in the world. They get their alluring red color from the presence of chromium. The largest supply of this mineral was harvested in Burma, which is known as the Mecca for rubies.

Gold

Many people think gold is the most valuable and most expensive mineral in the world, but this is a common misconception because there are other minerals that are far more worthy than gold. Still, it is a highly valued, expensive mineral.

Rhodium

Because of its rarity and industrial application, this silver-white noble metal is the world’s most expensive mineral. Rhodium became popular as a result of its highly valued catalytic application in the automotive industry. The largest supply of this mineral was found in 2009 in South Africa and Russia.

Lithium

This mineral which is commonly known as a crucial ingredient in the production of rechargeable batteries was first discovered in 1817 in Stockholm by the Swedish chemist Johan August Arfvedson. Lithium is a highly valued mineral which represents a billion dollar industry. The largest supplies of this mineral are found in Afghanistan.

Blue Garnet

Garnets can be found in various colors like brown, green, orange, pink, purple, red and yellow. Among all these colors the blue garnet is the only one with a considerably high value. This mineral was first discovered in the 1990s in Madagascar, and since then it has been mined in Russia, Turkey and the United States.

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WHY ARE DIAMONDS EXTRAORDINARY?

Very hard, very rare and very old, diamonds are essentially carbon that has been transformed under great pressure deep inside Earth. It is usually volcanic activity that brings them near the surface again after billions of years and makes mining possible. Diamonds are the hardest natural substance ever found.

  1. The ancient Romans and Greeks believed that diamonds were tears cried by the gods or splinters from falling stars, and Romans believed that Cupid’s arrows were tipped with diamonds (perhaps the earliest association between diamonds and romantic love).
  2. Diamonds are nearly as old as the earth and take billions of years to form deep in the pit of the earth. Very few diamonds survive the trip from the depths of the earth to the crust where they can be mined. No two diamonds are the same and carry their own unique properties such as internal inclusions and color. 
  3. Diamonds form about 100 miles below ground and have been carried to the earth’s surface by deep volcanic eruptions.
  4. Diamonds are made of a single element—they are nearly 100% carbon. Under the extreme heat and pressure far below the earth’s surface, the carbon atoms bond in a unique way that results in diamonds’ beautiful and rare crystalline structure.
  5. The word diamond derives from the Greek word “adamas,” which means invincible or indestructible.
  6. Diamonds are the hardest natural substance on earth ranking a 10 on the Mohs Scale of Hardness. The only thing that can scratch a diamond’s surface is another diamond.
  7. Diamonds have been valued and coveted for thousands of years by the likes of royalty and mythical beings. There is evidence that diamonds were being collected and traded in India as early as the fourth century BC. In the first century AD, the Roman naturalist Pliny is quoted as having said, “Diamond is the most valuable, not only of precious stones, but of all things in this world.”
  8. Ancient Hindus used diamonds in the eyes of devotional statues and believed that a diamond could protect its wearer from danger.
  9. Many ancient cultures believed that diamonds gave the wearer strength and courage during battle, and some kings wore diamonds on their armor as they rode into battle.
  10. During the Middle Ages diamonds were thought to have healing properties able to cure ailments ranging from fatigue to mental illness. 

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WHAT ARE MINERALS?

Minerals are natural chemicals from which Earth’s crust is formed. There are around 2000 individual minerals, each with a unique colour and shape. A few are powdery or resinous, but most are crystals. Some minerals, such as gold and silver, are pure chemical elements, but the majority are compounds, of which silicates are most common.

The earth is composed of mineral elements, either alone or in a myriad of combinations called compounds. A mineral is composed of a single element or compound. By definition, a mineral is a naturally occurring inorganic substance with a definite chemical composition and ordered atomic structure.

  • Table salt is a mineral called sodium chloride. Its ordered structure is apparent because it occurs in crystals shaped like small cubes.
  • Another common mineral is quartz, or silicon dioxide. Its crystals have a specific hexagonal shape. Coal is a mineral composed entirely of carbon, originally trapped by living organisms through the process of photosynthesis.
  • The carbon in coal is therefore of organic origin which leads some authorities to object to the definition of a mineral as an inorganic substance.
  • Limestone is a rock composed of a single mineral calcium carbonate. On the basis of their origin on earth rocks may be divided into three primary categories: igneous, sedimentary and metamorphic.

Minerals have been broadly classified into two classes, primary minerals and secondary minerals. Minerals which were formed by igneous process that is from the cooling down of the molten materials called magma, have been put in the primary category, while those formed by other processes have been put in the secondary category. Primary minerals which occur in the sand fractions of the soil had not undergone any change.

Other primary minerals had been altered to form the secondary minerals for example, the primary mineral mica had been altered to form the secondary mineral illite. Some other primary minerals for example, olivine, anorthite, hornblende etc., had been completely decomposed; the decomposition products recombined together to form the secondary minerals.

Minerals may be identified by their crystal structure, physical properties and chemical composition.

Like vitamins, minerals help your body grow, evolve and remain healthy. The body uses minerals to perform many functions — from building strong bones to nerve impulse transmission. Some minerals also create hormones or hold a regular heartbeat.

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ARE GEMS AND CRYSTALS THE SAME?

Crystals are glassy-looking, brittle solids that form shapes with sharp corners and flat sides. Natural crystals form when a liquid cools and hardens, and the molecules in the liquid cluster in a particular pattern – a pyramid, cube, etc.

Rare and beautiful crystals such as rubies and emeralds are valued as gems. Many are termed ‘precious’. They are rare because they only form naturally under very special conditions – usually deep within volcanic rocks.

Crystals are pure substances whose atoms, molecules, or ions are arranged in an ordered pattern, where they extend in all three spatial dimensions. A gem can be a crystal, while a crystal cannot be called as a gem.

Gemstone and Crystals are both used in various applications in today’s world. While gemstones are primarily used in jewelry and decoration pieces, crystals can be used in various applications such as healing, jewelry, vases, scientific purposes, etc.

Gemstones are rare pieces of minerals that are found in the ground, which are then cut and polished to be used in jewelry and other decorative pieces. Not all gems are minerals, such as lapis lazuli, a rock, and amber or jet, which are organic materials. A gemstone can also be known as precious or semi-precious stones. Precious stones include diamonds, emerald, ruby and sapphire, while the rest are qualified as semi-precious stones. Gemstones are classified by their color, translucency and hardness. Gems can also come with mineral bases like diamonds or rubies and with organic bases like amber. Today, geologists use the chemical composition of a gemstone to classify it into groups, species and varieties. The price of the gemstones depends on the rarity, color, composition, hardness and cut.

Crystals are pure substances whose atoms, molecules, or ions are arranged in an ordered pattern, where they extend in all three spatial dimensions. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification. Not all crystals need to be in solid formation, where water freezing also begins with small ice crystals that grow. Crystal symmetry requires that the unit cells stack perfectly with no gaps. Crystals are classified as Hexagonal, cubic, orthorhombic, tetragonal, rhombohedral, and monoclinic shapes. Crystals are light in color and are mostly translucent. The color of crystal is determined by the light passing through it.  Crystals are less expensive compared to gemstones. Salt and snowflakes are the most common types of crystals that are encountered.

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WHAT ARE SILICATES?

When silicon and oxygen, the two most common chemical elements on Earth, combine with a metal, they forma silicate. There are over 500 silicates that exist, quartz is one.

Silicate mineral, any of a large group of silicon-oxygen compounds that are widely distributed throughout much of the solar system.

The silicates make up about 95 percent of Earth’s crust and upper mantle, occurring as the major constituents of most igneous rocks and in appreciable quantities in sedimentary and metamorphic varieties as well. They also are important constituents of lunar samples, meteorites, and most asteroids. In addition, planetary probes have detected their occurrence on the surfaces of Mercury, Venus, and Mars. Of the approximately 600 known silicate minerals, only a few dozen—a group that includes the feldspars, amphiboles, pyroxenes, micas, olivines, feldspathoids, and zeolites—are significant in rock formation.

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What is diamond planet?

Imagine walking on a planet that is full of diamond. Dubbed 55 Cancri e, an exoplanet twice the size of Earth, is composed of carbon mostly in the form of graphite and diamond. At least a third of the planet’s mass is likely diamond as a result of the temperatures and pressures in the planet’s interior. Further observations are necessary to confirm the nature of the planet. It orbits a Sun-like hot star called 55 Cancri A. Planets like this are vastly different from our Earth, which has relatively less carbon.

Astronomers discovered the planet in 2004 after looking at the spectrum of its parent star, 55 Cancri A, one of two stars in a binary system about 40 light-years from Earth in the constellation Cancer. There are at least four other planets in the same system, mostly discovered before 55 Cancri e. The team (led by the University of Texas at Austin’s Barbara McArthur) discovered subtle tugs on the parent star that could be explained by the presence of yet another planet. While the planet’s existence was challenged by a second research team in 2005, a separate team in 2006 confirmed it. 

Astronomers initially thought 55 Cancri e (abbreviated 55 Cnc e) had an orbital period of 2.8 days, but measurements in 2011 showed that the planet is much closer to its parent star. Observations with Canada’s MOST (Microvariability & Oscillations of STars) space telescope demonstrated an orbital period of less than 18 hours. Researchers estimated the surface temperature of 55 Cancri e could be as high as 4,892 F (2,700 C). 

Follow-up observations with the Spitzer Space Telescope in 2012 showed that 55 Cancri e is much weirder than anticipated. While original estimates said the planet was dense and rocky, Spitzer suggested the planet includes a healthy proportion of light elements and compounds (such as water). However, the planet’s high surface temperatures contribute to a “supercritical” fluid state, the researchers said, meaning that the gases are in a liquid-like state. 

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WHAT IS THE STUDY OF FOSSILS CALLED?

Paleontology is the study of the history of life on Earth as based on fossils. Fossils are the remains of plants, animals, fungi, bacteria, and single-celled living things that have been replaced by rock material or impressions of organisms preserved in rock.

Paleontology, also spelled Palaeontology, scientific study of life of the geologic past that involves the analysis of plant and animal fossils, including those of microscopic size, preserved in rocks.

Paleontologists look at fossils, which are the ancient remains of plants, animals, and other living things. Fossils are mainly formed in two ways.

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WHY DID IT TAKE SO LONG FOR LIFE TO APPEAR?

Earth’s surface was probably molten for many millions of years after its formation. Life did not exist for the first 400-800 million years, and first began in water after the forming of the oceans.

Life seems to have started on Earth almost as soon as the surface cooled off enough to make it possible. However, complex animal life—everything from insects to fish to humans – took a lot longer to show up. Given that modern animals are a phenomenally diverse group that evolved relatively quickly, why were they so slow to get going?

The answer may be that animals are greedy: they need a lot of oxygen to grow big and complicated. Early Earth didn’t have much oxygen, but microbes changed the chemical content of the atmosphere over time from something alien and poisonous to us into the breathable air we have today. A new paper showed that the oxygen level as recently as 800 million years ago was only a tiny fraction of today’s – far too low to support oxygen-breathers like our ancestors and their relatives.

Life on Earth has always belonged mainly to microorganisms. Clouds are full of microbes; they have been found in deep mines and on the ocean floor. They outnumber and may even outweigh all other forms of life. If all animals vanished, most bacteria would still live on, but if all bacteria disappeared, we would die quickly.

The history of life on Earth reflects this as well. The first single-celled organisms appeared about 3.8 billion years ago, while the first known multi-cellular organisms evolved 2.1 billion years ago. However, these were “primitive” in our human-centric eyes: they didn’t have specialized organs for breathing or eating, much less brains for the wasteful activity we call “thinking”.

Then in the Cambrian era, around 570 million years ago, recognizably complex animal life evolved, including vertebrate ancestors. This change was relatively rapid in evolutionary terms, and a lot of diverse critters came out of it. Thus, something significant must have changed between 2.1 billion years and 570 million years to let animals diversify and complexity.

To explain this great change, scientists consider several possible explanations. One environmental (as opposed to genetic) idea: animals breathe in oxygen, so there needs to be enough oxygen in the air and water. Corals, sponges, and the like require less oxygen than crabs or fish, so oxygen levels limit what sorts of animals can evolve in a particular environment.

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WHAT IS THE TIMELINE OF LIFE ON EARTH?

Just as the day is divided into hours, minutes and seconds, geologists divide Earth’s history into time periods. The longest divisions are aeons, which are billions of years long; the shortest are chrons, a few thousand years long. In between come eras, periods, epochs and ages. Scientists divide the last 590 million years into three eras: the Palaeozoic (meaning ‘old life’), Mesozoic (‘middle life’), and Cenozoic (‘new life’).

Humans have only been a species in the most recent chapter of the history of Earth. The Earth was formed 4.6 billion years ago, when the sun in our solar system first formed, creating enough gravitational pull to spin planets into orbit. But how do scientists know how old the Earth is if humans weren’t around back when it was formed? When was life first formed on this planet? And what are the paths that life has taken so far over the course of that existence? This lesson will teach about the ages that make up the history of life on Earth, and explore the many changes and forms life has taken in its time on this planet.

Timeline of Geological Eras

The geological timeline of Earth is nearly identical to the history of life on Earth, apart from the Hadean Era. This is because the geological timeline, or the order of geological events, such as oceans forming, volcanoes erupting, how long deserts lasted, and tectonic plate movement, all happened in sequence with the life that has existed on this planet. The history of both life and the geological timeline is arranged within 5 subgroups, arranged from the largest span of time to the smallest: eons, eras, periods, epochs, and ages. To understand the timeline of life that has existed on Earth, it is important to understand how scientists determine the age of both rocks and the remnants of living things, otherwise known as fossils.

Because humans were not around 4.6 billion years ago to record the beginnings of our planet, scientists must rely on evidence from geological and fossil records in order to determine the relative age of both the planet and the life that exists here. Both the geological timeline and the age of life are determined in much the same way. Modern scientists rely on what is called radioactive dating to determine an accurate and precise age of both rocks and fossils. Radioactive dating measures the rate of decay of an element in a rock or in a fossil. Carbon-14 is typically used when dating fossils because all living things are carbon-based, and the flow of carbon can be tracked through the carbon cycle. For geological objects such as rocks and minerals, Rubidium-87 and Potassium-40 are often used. By knowing how long it takes for molecules in an object to decay, scientists can calculate when the object’s half-life is. The half-life of an object refers to the amount of time it would take for half of an amount of a substance to radioactively decay, or break down. If the half-life of an object is known, it is possible to calculate when the object was first created, when no decay is evident.

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WHAT IS THE PRIME MERIDIAN?

This is an imaginary line of 0° longitude that is perpendicular to the equator, and parallel to the axis. It passes through Greenwich in the UK, and divides Earth into eastern and western hemispheres. As it crosses the poles to the opposite side of the globe, the line becomes 180° longitude and is also known as the International Date Line.

The prime meridian is arbitrary, meaning it could be chosen to be anywhere. Any line of longitude (a meridian) can serve as the 0 longitude line. However, there is an international agreement that the meridian that runs through Greenwich, England, is considered the official prime meridian.

Governments did not always agree that the Greenwich meridian was the prime meridian, making navigation over long distances very difficult. Different countries published maps and charts with longitude based on the meridian passing through their capital city. France would publish maps with 0 longitude running through Paris. Cartographers in China would publish maps with 0 longitude running through Beijing. Even different parts of the same country published materials based on local meridians.

Finally, at an international convention called by U.S. President Chester Arthur in 1884, representatives from 25 countries agreed to pick a single, standard meridian. They chose the meridian passing through the Royal Observatory in Greenwich, England. The Greenwich Meridian became the international standard for the prime meridian.

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WHAT ARE LATITUDE AND LONGITUDE?

Every place on Earth’s surface can be pinpointed by two figures: its latitude and its longitude. Lines of latitude (called ‘parallels’) form rings around Earth, parallel to the equator. A place’s latitude is given in degrees (°) north or south of the equator, which is considered latitude 0°. On the other hand, lines of longitude (called ‘meridians’) run round Earth from north to south, dividing the world up like the segments of an orange.

A place’s longitude is given as degrees west or east of the prime meridian, which is longitude 0°.

Latitude and longitude are angles that uniquely define points on a sphere. Together, the angles comprise a coordinate scheme that can locate or identify geographic positions on the surfaces of planets such as the earth.

Latitude is defined with respect to an equatorial reference plane. This plane passes through the center C of the sphere, and also contains the great circle representing the equator. The latitude of a point P on the surface is defined as the angle that a straight line, passing through both P and C, subtends with respect to the equatorial plane. If P is above the reference plane, the latitude is positive (or northerly); if P is below the reference plane, the latitude is negative (or southerly). Latitude angles can range up to +90 degrees (or 90 degrees north), and down to -90 degrees (or 90 degrees south). Latitudes of +90 and -90 degrees correspond to the north and south geographic poles on the earth, respectively.
Longitude is defined in terms of meridians, which are half-circles running from pole to pole. A reference meridian, called the prime meridian , is selected, and this forms the reference by which longitudes are defined. On the earth, the prime meridian passes through Greenwich, England; for this reason it is also called the Greenwich meridian. The longitude of a point P on the surface is defined as the angle that the plane containing the meridian passing through P subtends with respect to the plane containing the prime meridian. If P is to the east of the prime meridian, the longitude is positive; if P is to the west of the prime meridian, the longitude is negative. Longitude angles can range up to +180 degrees (180 degrees east), and down to -180 degrees (180 degrees west). The +180 and -180 degree longitude meridians coincide directly opposite the prime meridian.

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HOW THICK IS EARTH’S CRUST?

Earth’s Crust

The crust is what we live on and is by far the thinnest of the layers of earth. The thickness varies depending on where you are on earth, with oceanic crust being 5-10 km and continental mountain ranges being up to 30-45 km thick. Thin oceanic crust is denser than the thicker continental crust and therefore ‘floats’ lower in the mantle as compared to continental crust. You will find some of the thinnest oceanic crust along mid ocean ridges where new crust is actively being formed. In comparison, when two continents collide as in the case of the India Plate and Eurasia Plate, you get some of the thickest sections of crust as it is crumpled together.

The temperatures within Earth’s crust will vary from air temperatures at the surface to approximately 870 degrees Celsius in deeper sections. At this temperature, you begin to melt rock and form the below-lying mantle. Geologists subdivide Earth’s crust into different plates that move about in relation to one another.

Given that Earth’s surface is mostly constant in area, you cannot make crust without destroying a comparable amount of crust. With convection of the underlying mantle, we see insertion of mantle magma along mid ocean ridges, constantly forming new oceanic crust. However, to make room for this, oceanic crust must subduct (sink below) continental crust.  Geologists have studied extensively the history of this plate movement, but we are sorely lacking in determining why and how these plates move the way they do.

Earth’s crust “floats” on top of the soft plastic-like mantle below. In some instances mantle clearly drives changes in the crust, as in the Hawaiian Islands. However, there is ongoing debate whether oceanic crust subduction and mid ocean ridge spreading is driven by a push or pull mechanism.

In very broad terms, oceanic crust is made up of basalt and continental crust is made up of rocks similar to granite. Below the crust is a solid relatively cooler portion of the upper mantle that is combined with the crust to make the  lithosphere layer. The lithosphere is physically distinct from the below-lying layers due to its cool temperatures and typically extends 70-100 km in depth.

Below the lithosphere is the asthenosphere layer, a much hotter and malleable portion of the upper mantle. The asthenosphere begins at the bottom of the lithosphere and extends approximately 700 km into the Earth. The asthenosphere acts as the lubricating layer below the lithosphere that allows the lithosphere to move over the Earth’s surface.

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HOW DOES EARTH GET ITS MAGNETIC FIELD?

The Earth’s outer core is in a state of turbulent convection as the result of radioactive heating and chemical differentiation. This sets up a process that is a bit like a naturally occurring electrical generator, where the convective kinetic energy is converted to electrical and magnetic energy. Basically, the motion of the electrically conducting iron in the presence of the Earth’s magnetic field induces electric currents. Those electric currents generate their own magnetic field, and as the result of this internal feedback, the process is self-sustaining so long as there is an energy source sufficient to maintain convection.

Unlike Mercury, Venus, and Mars, Earth is surrounded by an immense magnetic field called the magnetosphere. Generated by powerful, dynamic forces at the center of our world, our magnetosphere shields us from erosion of our atmosphere by the solar wind (charged particles our Sun continually spews at us), erosion and particle radiation from coronal mass ejections (massive clouds of energetic and magnetized solar plasma and radiation), and cosmic rays from deep space. Our magnetosphere plays the role of gatekeeper, repelling this unwanted energy that’s harmful to life on Earth, trapping most of it a safe distance from Earth’s surface in twin doughnut-shaped zones called the Van Allen Belts.

But Earth’s magnetosphere isn’t a perfect defense. Solar wind variations can disturb it, leading to “space weather” — geomagnetic storms that can penetrate our atmosphere, threatening spacecraft and astronauts, disrupting navigation systems and wreaking havoc on power grids. On the positive side, these storms also produce Earth’s spectacular aurora. The solar wind creates temporary cracks in the shield, allowing some energy to penetrate down to Earth’s surface daily. Since these intrusions are brief, however, they don’t cause significant issues.

Credit: NASA

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WHY IS THE CORE OF EARTH MADE OF IRON?

Because as Earth cooled, dense metal like iron sank to the centre, while lighter rock-forming materials floated to the top.

At the center of Earth is a solid iron inner core. The hot dense core has a radius of about 759 miles (1,221 kilometers) and a pressure of about 3.6 million atmospheres (atm).

Temperatures in the inner core are about as hot as the surface of the sun (about 9,392 degrees F or 5,200 degrees C) — more than hot enough to melt iron — but the immense pressure from the rest of the planet keeps the inner core solid, according to National Geographic.

The primary contributors to the inner core’s heat are the decay of radioactive elements such as uranium, thorium and potassium in Earth’s crust and mantle, residual heat from planetary formation, and heat emitted by the solidification of the outer core.

Earth’s inner core rotates in the same direction as the surface of the planet but rotates ever so slightly faster, completing one extra rotation every 1,000 years or so.

Credit: space.com

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WHAT HAPPENS WHEN PLATES COLLIDE?

Plates move at an average of between four and seven centimetres in a year. If plates collide along a deep trench beneath an ocean, one plate is pulled beneath another and melts and is recycled. On land, when continents collide, their edges are pushed up into new mountain ranges.

When two tectonic plates collide, they form a convergent plate boundary.

  • A convergent plate boundary such as the one between the Indian Plate and the Eurasian Plate forms towering mountain ranges, like the Himalayas, as Earth’s crust is crumpled and pushed upward.
  • In some cases, however, a convergent plate boundary can result in one tectonic plate diving underneath another. This process is called subduction. It involves an older, denser tectonic plate being forced deep into the planet underneath a younger, less-dense tectonic plate. When this process occurs in the ocean, a trench can be formed.
  • When subduction occurs, a chain of volcanoes often develops near the convergent plate boundary.

Credit: Byju’s

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WHAT IS EARTH MADE OF?

The structure of Earth can be divided into three parts: the crust, the mantle and the core. Made up from mainly oxygen and silicon, the crust is the outermost layer. It is the familiar landscape on which we live: rocks, soil and seabed. Beneath the crust is the mantle, a layer almost 3000 km deep. It is made of metal silicates, sulphides and oxides. This layer is so hot that the rock often flows like sticky road tar – only very, very slowly. Below the mantle is a core of metal, mostly iron, sulphur and nickel. The outer portion of the core is so very hot that the metal is always molten. The Earth’s magnetic field is created here. Earth’s inner core is even hotter – estimated to be around 6000 °C – but the metal is solid because pressure within the inner core is extreme, so the metal cannot melt.

1: The Core

The composition of the Earth begins with the inner parts of the planet. The Earth’s core is the densest part of the planet. It is made up of iron and nickel, and the core is so hot that is heats the rest of the planet around it. The core has chosen how the planet will be heated, and the core of the planet determines the equilibrium of the planet itself.

2: The Magma

The magma underneath the Earth’s surface spins around the world as it keeps the crust warm. The warmth of the magma can be felt in certain parts of the world where the ground is very close to the magma. The magma can be found rising out of the surface of the Earth at volcanoes and underwater cracks in the crust. The magma is the lifeblood of the Earth even though it is quite a scary thing to encounter today.

3: The Crust

The crust of the Earth is the ground that everyone walks on today. The crust is much thinner than the other components of the Earth, but it manages to support all the life on the planet. The Earth’s surface is covered with the crust completely, but much of the Earth’s surface is covered in water. Citizens of the Earth may never explore the floor of the sea, but that area is still a part of the Earth’s crust.

4: Magnetism

The magnetism of the Earth that helps it stay attached to the sun in orbit comes directly from the core. The core’s construction keeps the magnetism of the Earth going in ways that scientists do not understand completely. The magnetism created by the core also helps the Earth create a gravitational field that keeps everyone on the planet.

Credit: AES

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HOW DO WE KNOW WHAT EARTH’S INSIDE LOOK LIKE?

Scientists have worked this out from the vibrations from earthquakes and underground explosions. This data is pictured with lines on 3D maps to help scientists understand the structure of Earth’s core.

Core, mantle, and crust are divisions based on composition. The crust makes up less than 1 percent of Earth by mass, consisting of oceanic crust and continental crust is often more felsic rock. The mantle is hot and represents about 68 percent of Earth’s mass. Finally, the core is mostly iron metal. The core makes up about 31% of the Earth.

CRUST AND LITHOSPHERE

Earth’s outer surface is its crust; a cold, thin, brittle outer shell made of rock. The crust is very thin, relative to the radius of the planet. There are two very different types of crust, each with its own distinctive physical and chemical properties.Oceanic crust is composed of magma that erupts on the seafloor to create basalt lava flows or cools deeper down to create the intrusive igneous rock gabbro. Sediments, primarily muds and the shells of tiny sea creatures, coat the seafloor. Sediment is thickest near the shore where it comes off the continents in rivers and on wind currents.

MANTLE
The two most important things about the mantle are: (1) it is made of solid rock, and (2) it is hot. Scientists know that the mantle is made of rock based on evidence from seismic waves, heat flow, and meteorites. The properties fit the ultramafic rock peridotite, which is made of the iron- and magnesium-rich silicate minerals. Peridotite is rarely found at Earth’s surface.Scientists know that the mantle is extremely hot because of the heat flowing outward from it and because of its physical properties. Heat flows in two different ways within the Earth: conduction and convection. Conduction is defined as the heat transfer that occurs through rapid collisions of atoms, which can only happen if the material is solid. Heat flows from warmer to cooler places until all are the same temperature. The mantle is hot mostly because of heat conducted from the core. Convection is the process of a material that can move and flow may develop convection currents.

CORE
At the planet’s center lies a dense metallic core. Scientists know that the core is metal for a few reasons. The density of Earth’s surface layers is much less than the overall density of the planet, as calculated from the planet’s rotation. If the surface layers are less dense than average, then the interior must be denser than average. Calculations indicate that the core is about 85 percent iron metal with nickel metal making up much of the remaining 15 percent. Also, metallic meteorites are thought to be representative of the core.If Earth’s core were not metal, the planet would not have a magnetic field. Metals such as iron are magnetic, but rock, which makes up the mantle and crust, is not. Scientists know that the outer core is liquid and the inner core is solid because S-waves stop at the inner core. The strong magnetic field is caused by convection in the liquid outer core. Convection currents in the outer core are due to heat from the even hotter inner core. The heat that keeps the outer core from solidifying is produced by the breakdown of radioactive elements in the inner core.

Credit: Lumen Learning

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11-year-old boy finds 30,000-year-old woolly mammoth?

YEVGENY Salinde, an 11-year-old Russian boy, has found a 30,000-year old perfectly preserved mammoth carcass near his home in Russia’s far north. Experts believe this is the second most well preserved mammoth specimen ever discovered. A similar find like this hasn’t been encountered in a century.

Paleontologists did not only find a skeleton, like initially expected, but a complete carcass – skin, meat, fat hump, organs and a tusk. Scientists estimate the mammoth was 15 to 16 years old when it succumbed in the summer because it lacked an undercoat and had a large.

The total weight of the remains is more than 500 kg, and that includes the right half of the body with soft tissue, skin and hair, skull with one ear, a tusk, various bones and even reproductive organs, the Dolgano-Nentsky administration website announced.

It is believed to be the second best preserved mammoth discovery and the best mammoth find since 1901, when another mammoth was discovered near Beryozovka River in Yakutia, the paper reported.

Zhenya discovered the body 3 kilometres from Sopkarga polar meteorological station, where he lives with his family.

His parents informed scientific experts about the discovery after which the mammoth was taken to Dudinka in a helicopter and put in an ice chamber there. After the remains are studied, Zhenya the mammoth will move to Taymyr natural history museum as a showpiece.

Credit : NDTV

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What is doomsday fiction?

Imagine a world wrecked by a natural disaster, devastated by nuclear war, or destroyed by a pandemic. While this may sound all too familiar because of the prevailing COVID-19 pandemic, apocalypse fiction is a literary genre that has existed for many years. A subset of science fiction, apocalyptic and post-apocalyptic fiction, also known as doomsday fiction, imagines what life will be like at the end of the world.

How it began

An apocalypse is an event that results in mass destruction and change. Although apocalyptic themes exist in many religious texts, the 20th and 21st centuries have given rise to this genre. The aftermath of World War I, World War II, and the nuclear arms race proved to be fertile ground for writers and filmmakers to conjure up a world plagued by zombies, murderous robots, climate change and even a nuclear holocaust

Apocalyptic vs Post- Apocalyptic

Apocalyptic and post apocalyptic literature is set in a time period where the earth as we know it is coming to an end. An apocalyptic novel or film tells the story of the end of the world, unfolding during the timeline of the story. For example, the 2004 film, “The Day After Tomorrow shows what happens when a sudden worldwide storm plunges the entire planet into a new ice age. On the other hand, post-apocalyptic works portray life in the wake of a cataclysmic event. They focus on how the characters deal with the consequences of a disaster. A 2007 film “1 am Legend” starring Will Smith, is a good example. It follows Robert Neville, a scientist who is the last human survivor of a plague in the whole of New York, as he attempts to find a way to reverse the effects of the human-made virus.

Popular examples

Books written under this genre can be broadly classified (based on their themes) into post-disaster wastelands zombie apocalypse, nature gone wrong, machines taking over the world, and dystopian worlds. Here are a few examples.

Post-disaster wastelands

  • “The Stand” by Stephen King
  • “The Mad Max” film series by James McCausland and George Miller

Zombie Apocalypse

  • World War Z by Max Brooks
  • “The Walking Dead”, a graphic novel series by Robert Kirkman, Tony Moore, and Charlie Adlard

Dystopian worlds

  • “The Hunger Games” by Suzanne Collins
  • “Divergent” by Veronica Roth

Machines taking over

  • “The Maze Runner by James Dashner
  • The Big Melt” by Ned Tillman

 

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