What Is a Comet?
A comet is a huge ball of ice and space rock that orbits the sun deep in space. Occasionally, one passes near the earth and the sun. As the comet approaches the sun, heat boils off the ice. This creates a glowing cloud of gas, called the coma, which surrounds the nucleus (or solid part).
Besides heating up the comet, the sun’s radiation also sweeps some of the glowing gas and dust from the comet out into space, forming a long, glowing tail. Each time a comet goes around the sun, it loses some of it mass. Eventually, it must break up completely.
Comets are the largest objects in our Solar System. They can measure up to ten miles across and have tails that can extend millions of miles into space.
It’s said that the Greek philosopher Aristotle named them ‘comet’ from the Greek word meaning ‘hair of the head.’ Some famous comet’s are: The Great Comet of 1843, The Great Comet of 1884, The Hale-Bopp Comet, Donati’s Comet, and the Shoemaker Levy 9 Comet that hit Jupiter in 1994.