What is a comet primarily composed of?

A comet is primarily composed of ice, dust, and rocky material. This composition is often referred to as "dirty ice" because comets consist of frozen gases mixed with solid particulates such as dust and small rocks. When a comet approaches the Sun, the heat causes the ice to vaporize, releasing gas and dust. This process creates a glowing envelope, known as a coma, and often results in a tail that points away from the Sun due to solar wind. The presence of these diverse materials is crucial in understanding not only the lifecycle of comets but also the early solar system, as they are considered remnants from its formation.

Other options suggest different materials that do not accurately reflect the composition of comets. Some focus on individual elements or groups that do not encompass the unique icy and rocky nature of a comet, making them less representative of what defines these celestial objects.