What is comet??..............

A comet is a mass of ice and dust that moves around the sun and looks like a bright star with a tail. It is a small body in space. Sir Edmond Hilley, an astronomer took great interest in these comet. Many decades later, comet still remain a challenging mystery for the field of astronomy. From the research study in many space institutes around the world,it is declared that there are total 3628 comets moving around the space. Annually we can see one comet in average from our nakd eye in the sky from surface of the Earth.

By the definitions given by the various space research organizations, a comet can be defined as a space body that travels in an elliptical orbit around the sun. Most of the comets travel in elliptical orbits. When the comet comes in the vicinity of the star it is orbiting around, its comma-like tail gets illuminated. A majority of comets are visible only through telescopes and other aids. There are however, some comets which are also visible to the naked eye.According to the research and study,a comet is made up of ice, dust and different forms of gases. The nature of the components differs from comet to comet. The central part of a comet that looks like a ball is termed as the nucleus. The nucleus is made up of ice and frozen gases. The frozen components also include many other compounds like ammonia, methane and carbon dioxide. Rocks are another component of the nucleus. Due to such composition, the nucleus of the comet often resembles a huge ball of dirt and snow. It is also believed by some astronomers, that the nucleus of a comet is rather fragile because several comets have split into parts without any explainable reason except immense velocity.The huge elliptical orbit takes the comet in the range of heat of the star around its orbit. When the comet enters the inner parts of the solar systems, the frozen content of the nucleus starts melting. The gases and water within the nucleus vaporize as a result of radiation from the star and the solar wind. The immense velocity of the comet and the solar wind, push the vaporized matter away from the nucleus. This gives the comet it's distinct tail and the comma-like appearance. The high amount of heat and the ions (charged particles that are formed due to the heat of the sun) cause the tail of the comet to glow.
Comets are of two types according to their formation- short term comets and long term comets. Short term comets are originated in Kuiper belt as space bodies beyond the orbit of pluto. The main cause of origination of short term comets is the gravitational force of panets in the solar systems. These comets enter the solar systems and take the form of active and glowing comets. Whereas the long term comets are origated as travelling bodies in Oort cloud that is located 50,000 light years away from the Sun. Due to gravitational force of planets in solar systems these long term comets have elliptical orbits. As discussed above , comets have fragile structure so sometimes it splitas into many other small parts because of sheer velocity. The entry and exit of comets in the solar system in course of its orbit, reduces the amount of ice and gases in comets. Due to reduction it gets easily distributed into many parts. As asteroid is nothing but a dead comet of similar form in the space. Sometimes the comets also crash in other planets when their orbit crosses each other.
Many scientists and astronomers are studying about comets. It is hear breaking moment to gaze at a dying comet. The Halley’s comet is said to be the most beautiful comet that sparks and lighten everything and its beautiful tail. The other beautiful comet is Hale-Bopp, that was discovered in the year 1995.
Mark Twain, the famous writer, was born just two weeks after the sighting. He developed a very special liking towards the Halley's Comet. In his biography he comments,"I came in with the Halley's Comet, and expect to go with it. The Almighty has said no doubt, Now here are two unaccountable freaks; they came in together; they must go out together." Halley's Comet was next sighted on 20th April, 1910. Twain ended the journey of his life the very next day. The journey of any comet is indeed like that of Mark Twain. It is remarkably long, fast, adventurous as it streaks across the dark sky.