What Is a Comet?

Definition Comets are celestial bodies in orbit around the sun is elliptical or parabolic or hyperbolic . The word " comet " comes from the Greek , meaning " long hair " . Other terms were not shooting stars are not appropriate because the comet is not a star at all . Javanese people call it a cross because it has a tail like cubeb cubeb fruit that has been dried . Comets formed from ice and dust . Comets are composed of a collection of dust and gas that freezes when being away from the sun . When approaching the sun , some of the material making up comets evaporated to form the head and tail gas . Comets also orbit the sun , so it is included in the solar system . Comet is an incandescent gas with orbits different . Long " tail " comet can reach jutaankm . Several comets travel longer distances in space than planets . Some comets takes thousands of years to complete one orbit the sun . Parts of the comet The parts consist of a comet nucleus , coma , hydrogen cloud , and tail . Comet parts as follows : 1 . Core , is a very dense material , reaching several kilometers in diameter , and is formed from the evaporation of the materials making up the comet ice , which then turns into gas . (The head of the comet is a lump of rock and snow . ) 2 . Coma , is an area of ​​fog or veil -like regions around the nucleus . 3 . Hydrogen layer , the layer that envelops the coma , not visible to the human eye . Hydrogen cloud diameter of about 20 million kilometers . 4 . Tail , the glowing gas that occurs when the comet passes near the sun . Comet tail direction is always away from the sun . The tail of a comet consists of two kinds , namely tail of dust and gas tails . Form the dust tail was shaped arches , while the shape of a straight tail gas . Coma or tail of a comet as it approached the sun that is created when part of the core melted into gas . The solar wind then blew the gas, which resembles a puff of smoke toward the back of the head of the comet . Tail is seen shining from the earth . A comet has a tail and sometimes there are two or more . The types of comets Based on the shape and length of trajectory , comets can be classified into two , namely as follows . 1 . Long-tailed comet , the comet's trajectory with line very far through areas that are very cold in space so that the opportunity to absorb the gases are passed through the area . When approaching the sun , the comet to form a coma gas release and a very long tail . For example , comet Kohoutek passing near the sun every 75,000 years and Halley's Comet every 76 years. 2 . Short-tailed comet , the comet with trajectory lines are so short that have less opportunity to absorb the gas in the area in its path . When approaching the sun , the comet gas releases very little so just forming coma and tail is very short and almost no tail . Examples Encke comet passing close to the sun every 3.3 years. The names of the Comet Now it has been known by many names comets , among others, as follows . Comet Kohoutek . Komen Arend - Roland and Maikos which appeared in 1957 . Comet Ikeya - Seki , was discovered in September 1965 by two Japanese astronomers , namely Ikeya and T. Seki . Comet Shoemaker - Levy 9, which was destroyed in 1994 . Hyakutake comet that appeared in 1996 . Hale - bopp comet that appeared in 1997 .