What is the primary component of Saturn's atmosphere?

Hydrogen is the primary component of Saturn’s atmosphere. Above the visible cloud tops, Saturn’s atmosphere is composed of roughly 94 percent hydrogen and about 6 percent helium, with tiny amounts of methane, ammonia, water vapour, and other compounds.

The hydrogen-rich atmosphere reflects Saturn’s origin as a gas giant. The planet formed in the cold outer Solar System, where it accumulated large quantities of the light gases hydrogen and helium from the primordial solar nebula. As pressure increases toward the interior, hydrogen changes from an ordinary gas into dense fluid and eventually metallic hydrogen.

Helium is the main source of a common quiz mistake: it is abundant, but it is not Saturn’s primary atmospheric constituent. Methane and ammonia are present in much smaller quantities and help create chemical reactions and colourful cloud layers. Saturn’s visible bands and storms occur in this atmosphere, including winds near the equator that can reach about 500 metres per second, or roughly 1,100 miles per hour.