What is known as comet ?

Comets are frozen leftovers from the formation of the solar system composed of dust, rock and ices. They range from a few miles to tens of miles wide, but as they orbit closer to the sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet. This material forms a tail that stretches millions of miles. (Answer from NASA)

Some examples of comets are:

Comet Hyakutake

Halley's Comet

Comet Encke

Comet Hale-Bopp

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