Reference Terms
from Wikipedia, the free encyclopedia


A comet is a small body in the solar system that orbits the Sun and (at least occasionally) exhibits a coma (or atmosphere) and/or a tail - both primarily from the effects of solar radiation upon the comet's nucleus, which itself is a minor body composed of rock, dust, and ices.

Comets' orbits are constantly changing: their origins are in the outer solar system, and they have a propensity to be highly affected (or perturbed) by relatively close approaches to the major planets.

Some are moved into sungrazing orbits that destroy the comets when they near the Sun, while others are thrown out of the solar system forever.

Note:   The above text is excerpted from the Wikipedia article "Comet", which has been released under the GNU Free Documentation License.
Related Stories

Share This Page:

Space & Time News
October 5, 2015

Latest Headlines
updated 12:56 pm ET