Comets are sometimes referred to as what?

Comets are often referred to as "dirty snowballs" because they are composed primarily of ice and dust, creating a mixture that resembles a snowball. This term reflects the physical characteristics of comets: they contain a significant amount of volatile materials, such as water ice, carbon dioxide, ammonia, and other gases, along with solid particles of dust and rock. When a comet approaches the Sun, the heat causes the ice to vaporize, leading to the formation of a glowing coma and tail, which are iconic features of these celestial bodies. This unique composition and the way they behave in the solar system give rise to the nickname "dirty snowball," highlighting both their icy nature and the presence of non-icy materials.