Earth’s atmosphere

Definition

Earth's atmosphere is a layer of gases surrounding the planet, held in place by gravity. It protects life on Earth by blocking harmful solar radiation and reducing temperature extremes between day and night.

5 Must Know Facts For Your Next Test

1. The Earth's atmosphere is composed mainly of nitrogen (78%) and oxygen (21%).
2. It consists of five primary layers: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
3. The troposphere is where weather occurs and contains approximately 75% of the atmosphere's mass.
4. The ozone layer, found in the stratosphere, absorbs and scatters ultraviolet solar radiation.
5. Human activities like burning fossil fuels have increased levels of greenhouse gases in the atmosphere, contributing to climate change.

Related terms

Troposphere:

The lowest layer of Earth's atmosphere where most weather phenomena occur.

Stratosphere:

The second layer of Earth's atmosphere where the ozone layer is located.

Greenhouse Gases:

Gases such as carbon dioxide and methane that trap heat in Earth's atmosphere, leading to global warming.