Comet

The Nuttall Encyclopedia

A member of the solar system under control of the sun, consisting of a bright nucleus within a nebulous envelope, generally extended into a tail on the rear of its orbit, which is extremely eccentric, pursuing its course with a velocity which increases as it approaches the sun, and which diminishes as it withdraws from it; these bodies are very numerous, have their respective periods of revolution, which have been in many cases determined by observation.