A comet is a mountain of ice and dust, tumbling through space. When a comet approaches the sun, its ices sublimate (turn from solid to gas). Vapor, dust and gases stream out to form a hazy tail behind the comet.
Living on a Comet: 'Dirty Snowball' Facts Explained (Infographic)
Halley's Comet, a dusty ball of ice and frozen gases, spends most of its time in the chilly outland of the solar system.
(Image: © By Karl Tate, Infographics Artist)
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