Atmosphere

The Earth's atmosphere has no definite edge, slowly becoming thinner and vanishing into outer space. Three-quarters of the atmosphere's mass is contained within the first 11 km of the planet's surface. This lowest coating is called the troposphere. Further up, the atmosphere is usually separated into the stratosphere, mesosphere, and thermosphere. Away from these, the exosphere thins out into the magnetosphere. A vital part of the atmosphere for life on ground is the ozone layer.

The atmospheric stress on the surface of the Earth averages 101.325 kPa, with a scale height of about 6 km. It is 78% nitrogen and 21% oxygen, with trace amounts of other gaseous molecules such as water steam. The atmosphere protects the Earth’s life forms by captivating ultraviolet solar emission, moderating temperature, transporting water vapor, and provides useful gases. The atmosphere is one of the principal mechanism in determining weather and climate.

Because hydrogen gas is light and based on Earth's signify temperature, achieves break out velocity, unfixed hydrogen leaves the Earth. For this cause, the Earth's environment is oxidizing, with consequences for the chemical nature of life which developed on the planet.