ATMOSPHERE Pluto's atmosphere is thin, composed mainly of nitrogen, with traces of methane and carbon monoxide. It freezes as Pluto moves away from the Sun, forming a surface ice layer. During its closest approach to the Sun, this ice sublimates, creating a temporary atmosphere. Despite being incredibly thin, it can expand due to seasonal variations, with gases escaping into space. The atmosphere freezes and collapses as Pluto moves farther from the Sun. Its dynamic nature, influenced by Pluto's elliptical orbit, results in a changing and transient atmosphere.