E a r l y A t m o s p h e r e

The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbingultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation). The common name given to the atmospheric gases used in breathing andphotosynthesis is air. By volume, dry air contains 78.09% nitrogen, 20.95% oxygen,[1]0.93% argon, 0.039% carbon dioxide, and small amounts of other gases.

Composition of the sky

The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbingultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation). The common name given to the atmospheric gases used in breathing andphotosynthesis is air. By volume, dry air contains 78.09% nitrogen, 20.95% oxygen,[1]0.93% argon, 0.039% carbon dioxide, and small amounts of other gases.

2