thermosphere

American  

[thur-muh-sfeer] / ˈθɜr məˌsfɪər /

noun

1. the region of the upper atmosphere in which temperature increases continuously with altitude, encompassing essentially all of the atmosphere above the mesosphere.

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thermosphere British  

/ ˈθɜːməˌsfɪə /

noun

1. an atmospheric layer lying between the mesosphere and the exosphere, reaching an altitude of about 400 kilometres where the temperature is over 1000°C

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thermosphere Scientific  

/ thûr′mə-sfîr′ /

1. The region of the Earth's upper atmosphere lying above the mesosphere and extending from a height of approximately 80 km (50 mi) to between 550 and 700 km (341 and 434 mi) above the Earth's surface. In the thermosphere temperatures increase steadily with altitude, reaching as high as 1,727°C (3,140°F) at the highest elevations. Chemical reactions occur much faster here than on the surface of the Earth.

2. See also exosphere mesosphere stratosphere troposphere See illustration at atmosphere

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Etymology

Origin of thermosphere

First recorded in 1950–55; thermo- + sphere

Example Sentences

An overall increase in the number of geomagnetic storms this year has also caused the temperature in the thermosphere — the second-highest layer of Earth's atmosphere ― to reach a 20-year peak.

From Scientific American • Jul. 4, 2023

The extra CO2 pumped into the atmosphere down the years has cooled some of its highest reaches - the thermosphere.

From BBC • Nov. 16, 2021

Luckily for Morgan, he was able to send his ballot to Lawrence County’s Department of Voter Services electronically, from the thermosphere.

From Washington Post • Oct. 22, 2020

If you’re counting the distance to space in atmospheric layers, Virgin Galactic reached the bottom of the second-highest layer, known as the thermosphere.

From Washington Times • Dec. 21, 2018

By the end of 1967 it was hurtling through the thermosphere.

From New York Times • Sep. 9, 2011