Comets

Comets aer celestial bodies that revolve arround the sun forming an oval orbit. Comets consist of a colection of freezing dust adn gases, but if they pass close to the sun, they will melt then vaporize. A comet is often caled a hairy star, becaues when the comet moves, at the back part of it there is a gas spurt like a tail the length of which can reach millons of kilometers.

A comet consists of several parts, those are a core, coma, hydrogen layer, and tail. The core is a material in the form of very dense carbon compound. Coma is the atmosphere that is formed as the effect of ice materials that change to gas. Comet’s tail is made up of gases vapour of icy materials that are heated by the sun. The closer to the sun, a comet’s tail is geting longer and its direction always moves away from the sun.

Several examples of comets that have come into view and seen form the earth among others are as follows.

1. Halley’s comet, appears every 76 years.
2. Encke’s comet appeadr every 3 years.
3. Ikeya-seki’s comet appeared in 1965.
4. Kohoutek’s comet, appeared in 1973.
5. Wet’s comet, appeared in 1976.
6. Shoemaker-levy’s omet, appeared in 1993.

Reference:
Irawan, Etsa Indra dan Sunardi. 2008. Pelajaran IPA-Fisika Bilingual untuk SMP/MTs. Kelas IX. Bandung: CV.Yrama Widya.