Halley’s Comet

Nathan Reeves Geo 105 Professor Kerr 12-13-11 Halleys Comet Astronomers first observed Halleys Comet as far back as 200 BCE. The comets periodicity was first determined in 1705 by incline astronomer Edmond Halley, who it was eventually named after. Halleys Comet put up appe atomic number 18d in the inner Solar musical arrangement in 1986 and wont appear again until mid-2061. Although the nucleus of the comet itself is non that large, the coma give the bounce extend to a very large size.As the shove along molecules in the coma are ionized by the solar invisible radiation pressure from the solar wind, a stream of particles emitted by the Sun, pulls the comas ions turn out into a long tail, which may extend more than 100 zillionkilometers into space. The nucleus itself is only 15kilometers long, 8kilometers wide and 8kilometers thick. In comparison, the ground has a diameter of 12,756 km and the sun has a diameter of 1,392,000 km.This means that Halleys Comet is only about 4% the size of earth but because of its coma, it appears much larger to the naked eye. While the planets battleground around the sun, Halleys Comet scene of actions towards and away from the sun, all the way out to Jupiter, rectangular to the planets orbits. Halley is classified as a periodic or short-period comet, one with an orbit lasting 200 years or less. This contrasts it with long-period comets, whose orbits last for thousands of years.Most short-period comets, those with orbital periods shorter than 20 years and inclinations of 2030 degrees or less, are called Jupiter family comets. Those like Halley, with orbital periods of between 20 and 200 years and inclinations extending from nada to more than 90 degrees, are called Halley type comets. Only 54 Halley-type comets save been observed, compared with almost 400 identified Jupiter family comets. The orbits of the Halley-type comets uggest that they were railway lineally long-period comets whose orbits were altered by the s olemness of the giant planets and directed into the inner Solar System. If Halley was once a long-period comet, it is probably to convey originated in the Oort cloud a sphere of bodies that has an inner rim of 50,000AU. Also, the Jupiter family comets are believed to originate from the Kuiper belt, a flat disc of icy stack between 30AU and 50AU, from the Sun. An separate point of origin for the Halley type comets has been proposed.In 2008, a new object with a retrograde orbit similar to Halleys was discovered. Named Drac, its orbit takes it from just outside that of Uranus to twice the distance of Pluto. It may be a member of a new population of short Solar System bodies that serves as the source of Halley type comets. A a couple of(prenominal) things make Halleys Comet popular and unique. The obvious thing is that it is fairly gentle to collide with when it does orbit, more so than most other orbiting comets. Also, it orbits every 70 years or so.This makes it unique because it means that most people have a chance to see it at least once. Every multiplication of people gets an equal opportunity to see it ,which makes it special because now everybody can have a part in it. A lot of other comets only orbit every hundred years or so, so you just have to be lucky to be able to see them. References 1. ) http//csep10. phys. utk. edu/astr161/lect/comets/halley. html 2. ) http//nineplanets. org/halley. html 3. ) http//en. wikipedia. org/wiki/Halley%27s_Comet