Atmosphere of Earth Atmosphere of Earth The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity. The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation). By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water
Atmosphere of Pluto about distance to the orbiting moon. As early as the 1940s, Gerard Kuiper searched for evidence of the atmosphere in the spectrum of Pluto, without success. In the 1970s, some astronomers forwarded the hypothesis of a thick atmosphere and even oceans of neon: according to some views of those times, all other gases that are abundant in the Solar System would either freeze or escape. However, this hypothesis was based on a heavily overestimated mass of Pluto. No observational data about its atmosphere and chemical composition existed at the time. The first strong, though indirect evidence of the atmosphere appeared