Assertion: comet's atmosphere | /r/MadeOf | methane
Facets:
value: mainly
type: DEGREE
Source sentences:
text: The atmosphere of Enceladus is also extremely thin and variable, consisting mainly of water vapor, nitrogen, methane, and carbon dioxide vented from the moon's interior through cryovolcanism.
text: Pluto has an extremely thin atmosphere that consists of nitrogen, methane, and carbon monoxide, derived from the ices on its surface.