- the envelope of gases surrounding the earth or another planet.
"part of the sun's energy is absorbed by the earth's atmosphere"
. The gases of the atmosphere are held in place by the planet's gravity. Close to the surface the atmosphere is relatively dense. On Earth, three quarters of the atmosphere's mass is within 11 km of the surface. The atmosphere becomes less and less dense with the distance from Earth and finally fades away completely into space. Sometimes, an altitude of 100 km is regarded as the boundary between the atmosphere and outer space.
· The atmosphere of the Earth is divided into four layers. Closest to the Earth is the troposphere. This layer stretches from the surface of the planet up to an altitude of around 14 km.
· The mesosphere reaches from the top of the stratosphere up to almost 90 km. Most meteors heading for Earth burn up in the mesosphere. Further away there is the thermosphere and finally the exosphere which fades diffusely into space.
· There are no physical barriers between the layers. They can be distinguished by the way temperature relates to increasing altitude within the layers
· Above the troposphere lies the stratosphere. The stratosphere reaches about 50 km in altitude. The ozone layer is located in the stratosphere
· In addition to the stormy weather, the atmosphere can also carry dust and particles from the Sahara to North America.
Layer of gases that surrounds the Earth.
Info from: http://www.geography4kids.com/files/atm_introhtml
*Stop smoking,and less car use.