Category Science

Less than one month after Sputnik 1 had been launched, the Soviets claimed a second amazing achievement by sending the first living creature into orbit. Sputnik 2, which blasted off from Earth in November 1957, contained a small dog called Laika. The spacecraft was specially designed for the dog, with life-support facilities and a cradle. Laika survived the launch and the journey into space, but died when her supply of oxygen ran out in orbit. Three years later, in August 1960, two more dogs, named Belka and Strelka, became the first creatures to survive the journey into space and return, travelling aboard Sputnik 5.

Laika (Russian: 1954 – 3 November 1957) was a Soviets Space dog who became one of the first animals in space, and the first animal to orbit the Earth. Laika, a stray mongrel from the streets of Moscow, was selected to be the occupant of the Soviet spacecraft Sputnik 2 that was launched into outer space on 3 November 1957.

Little was known about the impact of spaceflight on living creatures at the time of Laika’s mission, and the technology to de-orbit had not yet been developed, so Laika’s survival was never expected. Some scientists believed humans would be unable to survive the launch or the conditions of outer space, so engineers viewed flights by animals as a necessary precursor to human missions. The experiment aimed to prove that a living passenger could survive being launched into orbit and endure a micro-g environment, paving the way for human spaceflight and providing scientists with some of the first data on how living organisms react to spaceflight environments.

Laika died within hours from overheating, possibly caused by a failure of the central R-7 sustainer to separate from the payload. The true cause and time of her death were not made public until 2002; instead, it was widely reported that she died when her oxygen ran out on day six or, as the Soviet government initially claimed, she was euthanised prior to oxygen depletion.

On 11 April 2008, Russian officials unveiled a monument to Laika. A small monument in her honour was built near the military research facility in Moscow that prepared Laika’s flight to space. It portrayed a dog standing on top of a rocket. She also appears on the Monument to the Conquerors of Space in Moscow.

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LUNA 2 was launched from the USSR in 1959, and was the first probe to visit the Moon’s surface, although it did not so much land as crash. Ranger 7, an American probe, also crashed on the Moon’s surface in 1964. It managed to take over 4000 close-up pictures. Luna 9 was the first probe to land successfully on the Moon in 1966. It sent back television pictures of the barren surface.

In January 1959, a small Soviet sphere bristling with antennas, Luna 1 was the first spacecraft to escape Earth’s gravity, a huge feat. Although Luna 1 did not reach the moon’s surface, as was likely intended, the spacecraft flew within about 4,000 miles of it. Its suite of scientific equipment revealed for the first time that the moon had no magnetic field.

Later in 1959, Luna 2 became the first spacecraft to land on the moon’s surface, making impact near the Aristides, Archimedes, and Autolycus craters. A third Luna mission subsequently captured the first, blurry, images of the far side of the moon.

Nine NASA Ranger spacecraft’s, launched between 1961 and 1965, gave scientists the first close-up looks at the moon’s surface. The Ranger missions were kamikaze-style; the spacecraft were engineered to streak straight toward the moon and capture as many images as possible before crashing onto its surface. In 1962, Ranger 4 was the first Ranger spacecraft to hit its target, the moon. Unfortunately, Ranger 4 slammed into the far side of the moon before collecting any scientific data.

Two years later, however, Ranger 7 streaked toward the moon and captured more than 4,000 photos in the 15 minutes before it smashed onto the surface. Images from all the Ranger missions, particularly Ranger 9, highlighted the moon’s rough terrain and the potential challenges of finding a smooth landing site.

In 1966, the Soviet spacecraft Luna 9 overcame the moon’s topographic hurdles and became the first vehicle to soft-land safely on the surface. The small craft was stocked with scientific and communications equipment and photographed a ground-level lunar panorama. Luna 10 launched later that year and became the first spacecraft to successfully orbit the moon.

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The soviet Yuri Alekseyevich Gagarin was the first person to be launched into space. He travelled aboard Vostok 1, and blasted off from Earth in April 1961. After completing one orbit, he returned safely to Earth. John Glenn was the first American to be sent into space in 1962.

April 12 was already a huge day in space history twenty years before the launch of the first shuttle mission. On that day in 1961, Russian cosmonaut Yuri Gagarin (left, on the way to the launch pad) became the first human in space, making a 108-minute orbital flight in his Vostok 1 spacecraft. Newspapers like The Huntsville Times (right) trumpeted Gagarin’s accomplishment.

Mercury astronaut Alan Shepard became the first American in space less than a month later. The first cooperative human space flight project between the United States and the Soviet Union took place in 1975. The Apollo-Soyuz Test Project was designed to test the compatibility of rendezvous and docking systems for American and Soviet spacecraft and to open the way for future joint manned flights.

Since 1993, the U.S. and Russia have worked together on a number of other space flight projects. The Space Shuttle began visiting the Russian Mir space station in 1994, and in 1995 Norm Thagard became the first U.S. astronaut to take up residency on Mir. Seven U.S. astronauts served with their Russian counterparts aboard the orbiting Mir laboratory from 1995 to 1998. The experience gained from the Mir cooperative effort, as well as lessons learned, paved the way for the International Space Station.

In-orbit construction on the Station began in November 1998, and it has been staffed non-stop with international crews since November 2000. The first Station crew, made up of U.S. commander Bill Shepherd and cosmonauts Yuri Gidzenko and Sergei Krikalev, was launched on board a Russian Soyuz spacecraft. The crew returned to Earth on the Space Shuttle Discovery in March 2001.

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Space launchers are rockets that carry payloads into space. Just as there are many sizes of truck to carry different goods from place to place, there are many different space launchers, each suited to different purposes. Rockets such as the Mercury-Atlas were designed to be small and light, as they only had to carry one man. Russia’s Soyuz series are incredibly powerful, able to carry 20 tonnes into a low-Earth orbit. NASA’s Saturn V was designed to be powerful enough to carry three men to the Moon.

NASA’s Space Launch System, or SLS, is an advanced launch vehicle that provides the foundation for human exploration beyond Earth’s orbit. With its unprecedented power and capabilities, SLS is the only rocket that can send Orion, astronauts and large cargo to the Moon on a single mission.

Offering more payload mass, volume capability and energy to speed missions through space than any current launch vehicle, SLS is designed to be flexible and evolvable and will open new possibilities for payloads, including robotic scientific missions to places like the Moon, Mars, Saturn and Jupiter.

Engineers are making progress toward delivering the first SLS rocket to NASA’s Kennedy Space Center in Florida for its first launch.

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Galaxies themselves may appear to be enormous, but even they do not exist independently in space. They gather together in groups — from pairs to clusters that can contain thousands of galaxies. The Milky Way is only one of a cluster of around 30 galaxies that make up the Local Group, an enormous collection of galaxies that stretches over millions of light years. The largest known cluster is the Virgo cluster, which contains over 2000 galaxies. Just as gravity causes galaxies to form clusters, it also brings clusters together to form superclusters. These are the largest structures in the Universe, stretching hundreds of millions of light years across space.

Groups of galaxies are the smallest aggregates of galaxies. They typically contain no more than 50 galaxies in a diameter of 1 to 2 megaparsecs (Mpc)(see 1022 m for distance comparisons). Their mass is approximately 1013 solar masses. The spread of velocities for the individual galaxies is about 150 km/s. However, this definition should be used as a guide only, as larger and more massive galaxy systems are sometimes classified as galaxy groups. Groups are the most common structures of galaxies in the universe, comprising at least 50% of the galaxies in the local universe. Groups have a mass range between those of the very large elliptical galaxies and clusters of galaxies.  Our own Galaxy, the Milky Way, is contained in the Local Group of more than 54 galaxies.

In July 2017 S. Paul, R. S. John et al. defined clear distinguishing parameters for classifying galaxy aggregations as ‘galaxy groups’ and ‘clusters’ on the basis of scaling laws that they followed. According to this paper, galaxy aggregations less massive than 8 × 1013 solar masses are classified as Galaxy groups.

Clusters are larger than groups, although there is no sharp dividing line between the two. When observed visually, clusters appear to be collections of galaxies held together by mutual gravitational attraction. However, their velocities are too large for them to remain gravitationally bound by their mutual attractions, implying the presence of either an additional invisible mass component, or an additional attractive force besides gravity. X-ray studies have revealed the presence of large amounts of intergalactic gas known as the intra-cluster medium. This gas is very hot, between 107K and 108K, and hence emits X-rays in the form of bremsstrahlung and atomic line emission.

The total mass of the gas is greater than that of the galaxies by roughly a factor of two. However, this is still not enough mass to keep the galaxies in the cluster. Since this gas is in approximate hydrostatic equilibrium with the overall cluster gravitational field, the total mass distribution can be determined. It turns out the total mass deduced from this measurement is approximately six times larger than the mass of the galaxies or the hot gas. The missing component is known as dark matter and its nature is unknown. In a typical cluster perhaps only 5% of the total mass is in the form of galaxies, maybe 10% in the form of hot X-ray emitting gas and the remainder is dark matter. Brownstein and Moffat use a theory of modified gravity to explain X-ray cluster masses without dark matter. Observations of the bullet Cluster are the strongest evidence for the existence of dark matter; however, Brownstein and Moffat have shown that their modified gravity theory can also account for the properties of the cluster.

Galaxies are classified using a very simple code that describes their basic shape. “E” is used to describe an elliptical galaxy, and a number from 0 to 7 is added to further define its form. An EO galaxy looks like a ball, whereas an E7 galaxy resembles a short, fat sausage. Spiral galaxies are defined by the letter “S”, and barred spiral galaxies by the letters “BS”. Both these forms of galaxy are given further definition by the addition of a letter a, b, .c or d. Galaxies with tightly wound arms are labelled Sa, and galaxies with looser arms are labelled Sd.

Galaxies are classified by shape. There are three general types: elliptical, spiral, and irregular. Perhaps the most familiar kind of galaxy is spiral galaxies. They have a distinctive shape with spiral arms in a relatively flat disk and a central “bulge”. The bulge has a large concentration of stars. The arms and bulge are surrounded by a faint halo of stars. The bulge and halo consist mainly of older stars, where spiral arms have more gas, dust and younger stars. Our Milky Way Galaxy is a spiral galaxy.

Some spiral galaxies are what we call “barred spirals” because the central bulge looks elongated – like a bar. In barred spirals, the spiral arms of the galaxy appear to spring out of the ends of the bar.

As their name suggests, elliptical galaxies are round or oval, with stars distributed fairly uniformly throughout. They have a bulge and halo, like spiral galaxies, but don’t have the flat disk of stars. The stars in ellipticals tend to be older.

Irregular galaxies have no identifiable shape or structure to them. They are often chaotic in appearance, without a bulge or any trace of spiral arms. The different shapes and orientation of galaxies are a result of their history, which may have included interactions with other galaxies.

Artist’s concept of Edwin Hubble’s galaxy classification system, created to classify galaxies depending on their appearance, This system is sometimes called Hubble’s Tuning Fork. At the left are elliptical galaxies, which are classified depending on how round they appear. The scale goes from E0 (the roundest) to E7, the most elliptical. Further to the right are lenticular galaxies, which are an intermediary class between ellipticals and spirals (classified SA0 or SB0, depending on if they have a bar at the core). To the right are the spiral galaxies, and they are classified depending on how tightly coiled (Sa, Sb and Sc) the spiral arms are (top branch), and if their core hosts a barred shape (bottom branch). The barred galaxies get the classification SBa, SBb and SBc, where SBa has the most tightly coiled arms.