What are comets mostly made of?

Comets are mostly made of ice, dust, and rocky materials. They are sometimes called “dirty snowballs” because they contain frozen gases like water, carbon dioxide, methane, and ammonia mixed with small pieces of rock and metal. Comets come from very cold parts of the solar system, such as the Kuiper Belt and the Oort Cloud. When a comet travels close to the Sun, the heat causes its ice to melt and release gas and dust, creating a glowing head and a bright tail. Studying comets helps scientists understand how the solar system formed.