Earth's Atmosphere Practice Flashcards

Vocabulary-style flashcards covering the formation, composition, layers, and characteristics of Earth's atmosphere based on lecture notes.

Photosynthesis

The process by which plants convert carbon dioxide and water into oxygen and hydrocarbons, serving as a source of early atmospheric oxygen.

Outgassing

The process of volcanoes erupting a variety of gases into the atmosphere, primarily consisting of water vapor, carbon dioxide, and nitrogen.

Nitrogen

The most abundant gas in Earth's atmosphere, making up $78\,\%$ of its composition.

Oxygen

An atmospheric gas that comprises $21\,\%$ of Earth's atmosphere; early Earth likely had none.

Argon

An atmospheric gas that makes up $0.93\,\%$ of Earth's composition.

Troposphere

The lowest layer of the atmosphere extending to about $12\,\text{km}$ (7 miles), where all weather occurs and temperature decreases with height.

Stratosphere

The atmospheric layer extending from $12\,\text{km}$ to $48\,\text{km}$ ($30\,\text{mi}$) that contains the ozone layer and where temperature increases with altitude.

Ozone layer

A region found in the stratosphere that protects Earth by absorbing ultraviolet (UV) rays from the sun.

Mesosphere

The coldest atmospheric layer, reaching to about $86\,\text{km}$ ($53\,\text{mi}$), with temperatures ranging from $30^{\circ}\text{F}$ to $-120^{\circ}\text{F}$ ($17^{\circ}\text{C}$ to $-100^{\circ}\text{C}$).

Thermosphere

The layer extending from $86\,\text{km}$ to $600\,\text{km}$ ($373\,\text{mi}$) where shooting stars and auroras occur and temperature increases with altitude.

Exosphere

The uppermost region of the atmosphere reaching $600+\,\text{km}$ ($400+\,\text{mi}$) where the atmosphere gradually fades into space and many satellites orbit.

Adiabatic cooling

The process where gases move up in elevation, experience less atmospheric pressure, expand, and consequently cool.

Tropopause

The boundary layer located between the troposphere and the stratosphere.

Runaway greenhouse effect

A phenomenon occurring on Venus caused by a carbon dioxide-rich atmosphere and no water left on the surface.

Gas giants

Planets that are primarily composed of hydrogen and helium.