Category Science

Why has Mars been chosen for human colonization?

For a planet to be habitable for humans, 1) it should be at a safe distance from the Sun – should be neither too hot, nor too cold; 2) it should contain liquid water, and 3) it should have a protective atmosphere that keeps the Sun’s radiation out. There is only one planet in the solar system that satisfies all these conditions and that planet is Earth. The next best option is Mars.

Mars has many advantages. It is very close to Earth – humans can reach the Red Planet in less than six months from Earth.

A Martian day is just over 24 hours long, roughly equivalent to a day on Earth. Mars has an atmosphere (though a thin one) that offers protection from cosmic radiation and solar radiation. Gravity on Mars is 38% that of Earth, which is believed by many to be sufficient for the human body to adapt to.

Evidence suggests that water may exist in the subsurface all over Mars. With help from technology, humans can survive on Mars, whereas the survival chances are slim on other planets and their moons.

 

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Why does a hermit crab need a shell?

The Mu Koh lanta national park in Southern Thailand had a rather unusual appeal to make to the public. The park authorities requested the public to donate cone-shaped shells they may have to the hermit crabs that have boomed in the last few months in the park. The population of the crustaceans, which protect themselves by wearing and living inside the discarded shells of other animals such as sea snails, has exploded on some islands in the Mu Koh Lanta national park Marine biologists believe the lack of visitors to the park in the backdrop of the COVID-19 pandemic could be a contributing factor. They feel that low number of tourists means fewer activities in the coastal areas, which could have led to the high survival rates of the hermit crabs.

As tens of thousands of hermit crabs thrive on the island, there is a serious shortage for shells. Some hermit crabs, having outgrown their previous homes, have moved into pieces of rubbish such as plastic cans, bottles, or caps. While going without a shell make them extremely vulnerable to their predators, living inside plastic homes is not safe either. The hermit crabs that climb into plastic bottles find the surface too slippery to get traction. Therefore, they cannot climb out of them. A 2020 study found that around 570,000 hermit crabs die annually from getting caught in plastic debris on two tropical islands in the South Pacific.

Plastic debris, in fact, creates a cascade of death for hermit crabs, because when a hermit crab dies, it releases chemical signal to other crabs conveying that its shell is available for occupation. This lures other crabs into the plastic container. One after the other hermit crabs get into the bottle or plastic can thinking they will get their next home, when in reality, it’s their last home.

Have you heard of the vacancy chain?

Hermit crabs begin their lives in larval forms on the seafloor. The larvae eventually metamorphose into small crabs, at which time they must search for their own shells. Hermit crabs are not true crabs – they do not grow their own shells, instead they have hard exoskeleton in the front and soft body in the back, which they protect using the discarded shells of other animals. As the hermit crab grows in size, it must find a larger shell and abandon the previous one.

These social animals display a fascinating behaviour when they are out to look for a new shell. At least 20 individual hermit crabs line up in size order – biggest to smallest – to see if a new shell turns up and who fits into it best. Their curled tail with a hook enables their bodies to fit inside these borrowed shells. Once a member fits into a new shell, it will eject itself from its former calcified castle and the next smallest will take this hand-me-down home, while leaving its older one for another and so on – the aim is that everyone walks away with a new shell that is a better fit than their old one! Scientists call this the vacancy chain.

 

Picture Credit : Google

What causes different seasons?

One of the many beautiful things about our planet is the changing seasons. At a period of time in the year, the Sun shines bright upon us making us rush to the nearest ice cream cart, at some other time we just want to stay at home tucked under layers of blankets.

As you experience the different seasons each year, have you wondered what causes them?

 A little tilt

Many believe that Earth’s seasons are caused due to Earth’s orbit around the Sun. because of its lopsided orbit (not a perfect circle), there are times when the Earth is closer to the Sun than other times. However, this is not the main reason. Earth has different seasons because of its tilted axis. Earth’s axis is an imaginary pole going right through the centre of Earth from top to bottom. Earth spins around this pole each day making different parts of the planet experience day and night. It is because of this tilted axis that Earth experiences different seasons.

Throughout the year, Earth’s tilted axis always points in the same direction. That’s why, as it orbits the Sun, different parts of the planet get the Sun’s direct rays. Sometimes the North Pole is tilted towards the Sun, giving us summer in the northern hemisphere, and sometimes the South pole tilts towards the Sun, giving us winter in the northern hemisphere.

But what caused the tilt?

Millions of years ago, when Earth was younger, it was hit hard by a big thing. That big thing is today known as the planet Theia. Theia carshed onto Earth and blasted a big hole on the surface of the planet. This sent huge amounts of dust and rubble out into space, which many scientists believe eventually turned into our moon. This major blow by Theia caused Earth’s axis to tilt, thereby giving us our seasons, and may be even our moon.

 

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What is the study of fish called?

Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of October 2016, with approximately 250 new species described each year.

The study of fish dates from the Upper Paleolithic Revolution (with the advent of “high culture”). The science of ichthyology was developed in several interconnecting epochs, each with various significant advancements.

The study of fish receives its origins from humans’ desire to feed, clothe, and equip themselves with useful implements. According to Michael Barton, a prominent ichthyologist and professor at Centre College, “the earliest ichthyologists were hunters and gatherers who had learned how to obtain the most useful fish, where to obtain them in abundance and at what times they might be the most available”. Early cultures manifested these insights in abstract and identifiable artistic expressions.

 

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What is the study of time called?

Horology is the study of the measurement of time. Clocks, watches, clockwork, sundials, hourglasses, clepsydras, timers, time recorders, marine chronometers, and atomic clocks are all examples of instruments used to measure time. In current usage, horology refers mainly to the study of mechanical time-keeping devices, while chronometry more broadly includes electronic devices that have largely supplanted mechanical clocks for the best accuracy and precision in time-keeping.

People interested in horology are called horologists. That term is used both by people who deal professionally with timekeeping apparatus (watchmakers, clockmakers), as well as aficionados and scholars of horology. Horology and horologists have numerous organizations, both professional associations and more scholarly societies. The largest horological membership organisation globally is the NAWCC, the National Association of Watch and Clock Collectors, which is USA based, but also has local chapters elsewhere.

There are many horology museums and several specialized libraries devoted to the subject. One example is the Royal Greenwich Observatory, which is also the source of the Prime Meridian (longitude 0° 0′ 0″), and the home of the first marine timekeepers accurate enough to determine longitude (made by John Harrison). Other horological museums in the London area include the Clockmakers’ Museum, which re-opened at the Science Museum in October 2015, the horological collections at the British Museum, the Science Museum (London), and the Wallace Collection.

 

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Which is the study and practice of making maps called?

Cartography or mapmaking is the study and practice of making maps. Map making involves the application of both scientific and artistic elements, combining graphic talents and specialised knowledge of compilation and design principles with available techniques for product generation. Maps function as visualization tools for spatial data. Spatial data is stored in a database and extracted for a variety of purposes. The traditional analog methods of map making have been replaced by digital systems capable of producing dynamic interactive maps that can be manipulated digitally.

Modern Cartography like many other fields of “information technology” has undergone rapid changes in the last decade. Rather than merely drawing maps the cartographic process is concerned with data manipulation, data capture, image processing and visual display. Cartographic representations may appear in printed form or as dynamic images generated on a computer display screen. Computer assisted mapping systems have added a new and exciting dimension to cartographic techniques and traditional methodologies have to be augmented with new skills. The fundamental nature of cartography has changed with the evolving technologies, providing cartographers with new methods for visualization and communication of spatial information.

 

Picture Credit : Google