Coma (Astronomy)
This is the current revision of Coma (Astronomy) as edited by Ed Poor (talk | contribs) at 23:26, August 11, 2007. This URL is a permanent link to this version of this page.
It has been suggested that this article or section be merged with [[::comet|comet]]. (Discuss)
A Coma is a spherical cloud of material surrounding the head of a comet. This material is mostly gas that the Sun has caused to boil off the comet's icy nucleus. This gas shines both by reflected sunlight and light emitted by excited molecules. A cometary coma can extend up to a million miles from the nucleus.