A Brief note on Comets

Comets are small asteroids that are made up of volatile ice. It orbits around the sun. Comets have a long-range orbital period i.e., ranging from several years to millions of years. The comets that have short-period originate in the Kuiper belt or in a scattered disc that is beyond the orbit of Neptune. The comets that have long-period are believed to originate in the Oort cloud. 

Body

Comet meaning

The meaning of comet is that it is small irregular-shaped asteroids that are made up of volatile grains and frozen gases, which orbit around the sun. The ice sublimates when the comet comes close to the sun i.e., the ice directly converts from solid to gas form, this process of releasing gas by the comet is called outgassing. The process of outgassing produces a visible atmosphere which is called a coma (almost 15 times the earth’s diameter), and sometimes also possesses a tail (maybe of one astronomical unit). These events occur due to the effects of solar wind and solar radiation which acts upon the nucleus of the comet. The nuclei of the comet are made up of dust, small rocky particles, and ice which range from a few kilometres to tens of kilometres across. Comets come close to the sun due to the highly elliptical orbit that they have and sometimes due to the same comet swinging deeply into space frequently going beyond Pluto. Sometimes the comets are seen from the earth without the help of a telescope, this happens due to the brightness of the comets. Comets for a long time were thought as something that is filled up with poisonous gas, ghosts, demons, or cosmic signs but it is a simple asteroid covered with ice. From the formation of the solar system, comets are the only left primitive body, therefore for scientists, comets are very important. In the outer region of the solar nebula, comets are formed where it was cold enough for condensation. 

Meteoroids

A meteoroid refers to a metallic body that is a very small object which travels through space. A meteor is known as a small burning metallic substance that travels through space. Whereas meteorite is the small rocky metallic substance that has already hit the earth. Meteoroids are the part of the rock that is broken off from large asteroids or comets in the solar system. Sometimes these meteoroids are formed by collisions with the planet. The measurement of meteoroid orbits is average about 20 km/s (45,000 mph). 

The basic features of meteors are

When meteoroids collide with the earth’s atmosphere with high-velocity then meteors are formed. Several meteors are seen per hour in the clear night sky. A meteor can last from a small fraction of a second up to several seconds. The meteors that are visible in the sky vary in brightness, emit flames or sparks, sometimes meteors also leave a trail behind them while moving. The meteors which leave the tail or the luminous meteors are termed bolides or fireballs. The phenomenon is called a meteor shower when the rate of meteors increases significantly more than normal. The meteors are called sporadic when they do not shower. The object size of a grain of sand may start at an altitude of 100 km (60 miles) or higher when a typically visible meteor is produced. 

Conclusion

It is to conclude that the comet is small irregular shaped asteroids that are made up of volatile and frozen gases, which orbit around the sun. The ice sublimates when the comet comes close to the sun i.e., the ice directly converts from solid to gas form, this process of releasing gas by the comet is called outgassing. From the formation of the solar system, comets are only left as a primitive body, therefore for scientists comets are important