What are the main parts of a comet?

• A. Nucleus and coma only
• B. Nucleus, tail, and coma
• C. Dust and gas are the only components
• D. Nucleus, coma, and tail

Answer: (D)

A comet’s structure centers on three features: the solid nucleus, a surrounding coma, and a tail that streams away from the Sun. The nucleus is the dense, rocky-icy core; when the Sun warms the comet, ices sublimate and eject material, creating the glowing coma around the nucleus. The escaping material is pushed by solar radiation and the solar wind, forming a tail that always points away from the Sun and can include both a dust component and an ionized gas component. So the three main parts are the nucleus, the coma, and the tail. The other options miss one part or misidentify what makes up the comet, whereas this trio fully describes its visible structure.