n, which makes it start to disappear. The ice and gasses start evaporating, which leaves the dust and other solids left. When this happens, meteors are formed. The orbit of planets and comets are alike because they travel in an ellipse with the sun as the center point. However, for the planets the orbit is more in a circular shape. Also, the planets orbit the sun on the same plane. However, most comets, including comet Hyakutake, which was visible in 1996, and Hale-Bopp that was in 1997, have elliptical orbits of that are very large in size, and are shaped more like an oval than a circle shape. The foci of these comets are very far apart from each other. The plane of comet Hyakutake's orbit intersected the planetary orbit plane at a steep angle. The plane of Hale-Bopp is nearly perpendicular to the plane of earth's orbit. One of the most well known comets is Halleys comet. This comet has been known since around 240 BC, and maybe even as early as 1059 BC. Its most famous appearance was in the year 1066 AD, when it was seen right before the Battle of Hastings. The comet was named after Edmund Halley, who is the one who calculated its orbit. He figured that the comets that were seen in 1531 and 1607 were the same thing, which meant it had an orbit of 76 years. Halley died, however in 1742, so he never lived to see his if he was right. His prediction did come true though when the comet came back on Christmas Eve in 1758. Halley's Comet came in the years 1835 and 1910. Then in 1984 to 1985, five spacecraft from the USSR, Japan and Europe were sent to make observations and study Halley's Comet in 1986. One of the deep space satellites from NASA was changed so it could observe the solar wind upstream from the comet Halley. Only three comets have ever been studied from a spacecraft. Comet Giacobini-Zinner was one of the comets studied from space; it was in 1985. Comet Halley was studied in 1986. Comet Grigg-Skjellerup was studied on July 10th, ...
