Which celestial bodies are often referred to as “dirty snowballs”?

Comets are commonly referred to as “dirty snowballs” because of their composition and appearance.

Comets consist of ice, dust, stony debris, and organic substances. An extended atmosphere called a coma forms around the comet’s nucleus, along with a tail composed of gas and dust particles blown outwards by the solar wind. This technique results in a brilliant, fuzzy ball encircled by a glowing halo that resembles a dirty snowball.