What is a comet?

Comets are small celestial bodies in our solar system made mostly of ice, dust, and rocky materials. When they approach the Sun, heat causes their ices to vaporize, forming a glowing coma and often a visible tail that streams away from the Sun. Comets are sometimes called 'dirty snowballs' and are thought to be remnants from the early formation of the solar system, offering scientists clues about its origins. They travel in elongated orbits that can take them far beyond the planets before returning toward the Sun.