Explanation

Comets are small celestial bodies made mostly of ice, dust, and rocky material. They follow elongated orbits around the Sun. When a comet approaches the Sun, its icy surface begins to vaporize, forming a glowing coma (a cloud of gas and dust) around the nucleus, and sometimes developing a visible tail that points away from the Sun due to solar wind. These orbits can vary widely in shape, some being highly elliptical, which means they can take comets very close to the Sun at their perihelion (closest approach) and far away into the outer reaches of the solar system at their aphelion (farthest point). However, regardless of their shape, all comet orbits are ultimately controlled by the gravitational pull of the Sun.