SOLAR SYSTEM

Detailed explanation-1: -Comets are collections of rocky material and ices, sometimes referred to as “dirty snowballs”. One of their key features is their large abundance of so-called “volatile” compounds, things like carbon dioxide, water and noble gases that sublimate (change from solid to gas) very easily.

Detailed explanation-2: -A model of a comet’s nucleus, proposed by F. L. Whipple in 1949, and confirmed by the Giotto space probe to Halley’s Comet in 1986. According to this model, cometary nuclei consist of a relatively solid conglomerate of frozen ices and dust, rather than a loose ‘flying sandbank’ as suggested by an alternative model.

Detailed explanation-3: -Comets are loosely packed dirty snowballs, formed of various ices (i.e. water, carbon dioxide, methane, ammonia, carbon monoxide, and cyanide/cyanogen) as well as dirt and rocks.