Meteor Showers, A Cosmic Wonder

Have you ever wondered about this cosmic wonder called meteor shower? How is a meteor shower? Why is this meteor shower? Our today's article is about the details of this meteorite.

When we look at the sky during the day, what do we see? When looking for the answer to this question, various environmental conditions will peek into our minds. If the sky is covered with thick clouds, then nothing but clouds can be seen. And if there is a cloudless sky, will there be much difference? No. Because, due to the effect of bright sunlight, nothing will be visible anymore. Of course, flying birds or airplanes should be left out. But in the afternoon, when the evening is coming, the dark wings are spreading and devouring the earth, then a door of cosmic wonder opens before our eyes. In the cloudless night sky, “full bread” can be seen as the full moon, fixed bright stars, or hundreds of twinkling stars. The moon, the only natural satellite of our earth, enhances the beauty of the night sky with its presence. Another special type of cosmic object is occasionally seen in the night sky. When we enjoy the beauty of the night sky with the naked eye, we sometimes see some light-like objects rushing towards the earth across certain areas made up of long-tailed comets. These special flammable objects, if they burn to ashes before the earth falls to the surface, we call them "meteors". That is, a meteorite is a small cosmic object made of rock or metal orbiting in space that ignites in a collision with the air as it enters the Earth's atmosphere. And if it hits the earth without being exhausted in the atmosphere, then I call it a meteorite. These two coincide with meteor showers.

Meteorites are much smaller in size than asteroids. When a meteorite enters the Earth's atmosphere, its speed is about 20 km per second. Most meteors come from an elliptical asteroid belt between the solar system's planets Mars and Jupiter. In addition to these asteroid belts, meteors may also have originated in the interior of the solar system. For this reason, evidence has been found that a number of meteors found on Earth have originated from the moon or Mars. What happens when an extraterrestrial object enters the Earth's atmosphere? The pressure, temperature, material, mass, etc. of the object varies. What else happens? Objects collide with atmospheric elements and chemical reactions take place. As a result, the internal temperature of the object rises so much that it burns the outer surface of the meteor. During this time, aerodynamics heat causes bright light to shine and is called a "shooting star". Some meteors originate from the same source and break up into smaller tiny parts called meteor showers.

Depending on the method of collecting meteors, they are divided into two classes. If it is visible during a meteor fall and then collected, it is called "FALL", and if it is collected in any other way, it is called "FIND". Typically, meteors are divided into three groups. These are -

• Stony meteorites: These are mainly composed of silicate minerals. Most meteors fall into this category. About 86% of the total meteorites found on Earth belong to this group.
• Iron meteorites: These are mainly composed of iron-nickel metal. About 6% of the total meteorites found on Earth belong to this group.
• Stony-Iron meteorites: These are composed of a mixture of iron-nickel metal and silicate minerals. The remaining 8% belong to this group.

Continuous and advanced research on meteors has further divided their knowledge about their chemical composition and the presence of minerals into more different classes and subcategories. There is no room for detailed discussion in this article.

Most meteors break into pieces immediately after entering the Earth's atmosphere. Studies show that 18000-84000 meteors larger than 10 grams reach the earth's surface, of which only 5 to 6 pieces a year reach. Wherever a meteorite falls on the surface of the earth and is discovered, the naming is done accordingly. And if multiple meteors are found in the same place, they are named in the order. The size of the meteor can be different. Its diameter can range from a few millimeters to several meters. When a large meteorite falls on the earth's surface, a very large volcano is formed on the earth's surface. If we look back today, we can see that in the past, meteorites have caused many volcanoes to collide with the Earth's surface, with some of the dinosaurs becoming extinct.

Although meteors can be found anywhere on Earth's surface, the collection of both FALL and FIND meteorites is limited to most parts of the continent of Antarctica. And then the area from which they are collected is the desert area. And very little has been collected from the rest of the world and from other continents, including the seas and oceans. This does not only mean that meteorites fall in large numbers in Antarctica or desert areas, but also that the geographical nature of both areas is conducive to their discovery. More than 98% of Antarctica's surface is covered by snow and ice. Ice-free areas account for only 2% of the total area, including hills, Nunatak and Oases. Nunatak are open, a bridge of rocky material, a bare mountain peak or a huge ice field or glacier. It is also called an ice island. The term Nunatak is commonly used where there is the presence of a permanent iceberg. Oases are a small fertile land or oasis in the desert where a spring usually prevails. The largest ice-covered place on Earth's surface is Antarctica, which is moving northward at a certain speed throughout the year due to its own weight and gravity. Meteors have been falling over Antarctica, covered by continuous and thick snow, for the past several million years. Where there are mountains and Nunatak, the continuous motion of polar ice caps slows down because they act as barriers. This differential movement of ice flow helps lower snow or ice layers to reach the glacier surface. In the southern summer (November-March), high winds and rising temperatures cause the upper part of the iceberg to melt, changing the location of meteorites trapped in thick ice; Moves away from the place of collapse and condense near the edge of the iceberg. Meteorites can be easily identified in this potential region because of the color difference between blue ice and dark meteorites. By studying this important phenomenon, many meteorites have been collected from Antarctica. Even in desert areas, meteorites can be identified by the color difference between dusty sand and dark meteorites. As the different colors of other terrestrial objects merge with the dark colors of meteorites, their presence in other places becomes much more difficult to detect and collect.

Although scientific advances have taken us much further, we still do not know much about the vast and cosmic space beyond our own earth. Since meteorites enter the Earth's atmosphere from cosmic space, their study also helps us understand the origin of the cosmic structure or many other planets as well as their structure. It has not yet been possible for humans to reach any other planet on their own, but the meteorite from that planet has come to Earth and is giving us various clues about the structure and origin of that planet, on the basis of which a detailed scientific investigation is underway. The origin of life and one of the elements of life, carbon, hydrogen, nitrogen, and oxygen - as well as their addition and subtraction, are studied from these meteorites In the future, detailed study of meteorites is expected to be considered as a way to find out the existence of life on other planets and cosmic space.

The Geological Survey of India (GSI) is responsible for all meteorites found in India. GSI collects these and retains all information on the subject. Meteorites have been collected from all over India and are housed at the Meteor Museum in Kolkata, the headquarters of GSI. A meteor research program began in 2012 during the 32nd Indian Scientific Expedition to Antarctica. A team of researchers from the Physical Research Laboratory (PRL), Radio Physics, University of Calcutta, Ahmedabad, is conducting scientific research on meteorites.

Finally, it can be said that meteorite research could open up new horizons for understanding the origin and evolution of planets and other cosmic objects. Undoubtedly, all the information about the universe that has not yet been uncovered can be found in this study. Thus, scientific collection of meteorites and their research should be encouraged and given due importance.