Astronomy Answers
From the Astronomical Dictionary

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The description of the word you requested from the astronomical dictionary is given below.

the comet

komètès = [Greek] with long hair

A comet is a block of ice and dust with perhaps a rock in the middle, that orbits around the Sun. Most comets come from far beyond the furtherst planet and fly through the inner part of the Solar System in a short time. When comets come close enough to the Sun, then they usually develop a coma and one or more tails.