Comet

A comet is a small celestial body that orbits the Sun and (at least occasionally) possesses a coma (or atmosphere) and/or a tail — both due primarily to the effects of solar radiation upon the comet's nucleus, which itself is a minor planet composed of rock, dust, and ices. Due to their origins in the outer solar system and their propensity to be highly affected (or perturbed) by relatively close approaches to the major planets, comets' orbits are constantly changing. Some are moved into sungrazing orbits that destroy the comets when they near the Sun, while others are thrown out of the solar system.
== Physical characteristics ==
== Orbit ==
== Nomenclature ==
== History of comet study ==
Comet Hyakutake
== External links ==