Comet

From SPACEwiki

A Comet is a small Solar System body that has a coma and/or a tail and is bigger than a Meteoroid. When close enough to the Sun, a comet exhibits a visible coma (fuzzy "Atmosphere"), and sometimes a tail, both because of the effects of solar radiation upon the comet's Nucleus. Comet nuclei are themselves loose collections of ice, dust and small rocky particles, ranging from a few hundred metres to tens of kilometres across.

[edit] Name and symbol

The word comet came to the English language through the Latin cometes from the Greek word komē, meaning "hair of the head"; Aristotle first used the derivation komētēs to depict comets as "stars with hair." The Astronomical symbol for comets accordingly consists of a disc with a hairlike tail.