What does mesosphere mean?
The mesosphere is a layer of the atmosphere above the stratosphere and below the thermosphere. On Earth, it begins at an altitude of roughly 50 kilometres and extends to about 85 kilometres, although its boundaries vary with latitude, season, and atmospheric conditions. It is best known as the coldest layer of the atmosphere, with temperatures near its upper boundary sometimes dropping below −90 °C. The mesosphere is also where many incoming meteoroids ignite and disintegrate, creating the familiar streaks of meteors. Because of its altitude and low temperature, this layer is of particular interest to atmospheric scientists, astronomers, and engineers studying atmospheric waves, meteors, and spacecraft re-entry. The word is primarily used in scientific and geographical contexts, especially in discussions of Earth's atmosphere but also in descriptions of comparable layers on other planets.
nounThe mesosphere is the layer of Earth's atmosphere between the stratosphere and the thermosphere, extending roughly 50–85 kilometres above the surface. It is the coldest atmospheric layer, with temperatures that can fall below −90 °C.
- The layer of a planet's atmosphere between the stratosphere and thermosphere, especially the layer of Earth's atmosphere extending roughly 50–85 kilometres above the surface.
"Meteors commonly burn up in the mesosphere, producing bright streaks of light."
"The spacecraft passed through the upper mesosphere during re-entry."
"Scientists use the mesosphere to study how atmospheric waves and meteors behave at high altitude."
The plural is uncommon but is used when discussing corresponding layers in the atmospheres of different planets.
"Researchers compared the mesospheres of Earth and Mars."
The mesosphere is the place where meteors meet their fiery end—and where the atmosphere is colder than anywhere else on Earth.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does mesosphere come from?
Mesosphere was formed in the early 20th century from the combining form meso-, meaning “middle,” and the Greek-derived word sphere, referring to a spherical body or region. The name reflects its position between the stratosphere below and the thermosphere above. Its formation belongs to a series of atmospheric-layer names that share the suffix -sphere, including troposphere, stratosphere, and thermosphere.
Related word forms
How mesosphere is actually used
Mesosphere is primarily a formal scientific and geographical term. In Earth-science usage it is usually treated as a named layer of the atmosphere; when discussing other planets, the term can refer to an analogous atmospheric region.
Easily confused with mesosphere
The stratosphere lies below the mesosphere and contains the ozone layer, whereas the mesosphere is the colder layer immediately above it.
The thermosphere lies above the mesosphere and includes much of the upper atmosphere in which auroras occur.