thermosphere
noun
ther·mo·sphere
ˈthər-mə-ˌsfir 
: the part of the earth's atmosphere that begins at about 50 miles (80 kilometers) above the earth's surface, extends to outer space, and is characterized by steadily increasing temperature with height
Examples of thermosphere in a Sentence
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The ignorosphere includes the mesosphere — the layer of Earth's atmosphere at altitudes between 30 and 53 miles (50 to 85 kilometers) — plus a section of the thermosphere up to an altitude of 100 miles (160 km).
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Tereza Pultarova, Space.com, 16 Aug. 2025
Greenhouse gas emissions here at ground level are wreaking havoc on the upper atmosphere, earth’s thermosphere, which potentially can cause catastrophic satellite collision in low-Earth orbit.
—Bruce Dorminey, Forbes, 12 Mar. 2025
The scientists used computer models to simulate how CO2 would influence the thermosphere and satellite orbital dynamics under different emission scenarios.
—Margherita Bassi, Smithsonian Magazine, 12 Mar. 2025
While modeling from the 1990s already showed that greenhouse gases trap heat in the lower atmosphere, more recent research determined that the same gases also radiate heat at much higher altitudes — thereby cooling the thermosphere.
—Sharon Udasin, The Hill, 10 Mar. 2025
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Tereza Pultarova, Space.com, 16 Aug. 2025
Greenhouse gas emissions here at ground level are wreaking havoc on the upper atmosphere, earth’s thermosphere, which potentially can cause catastrophic satellite collision in low-Earth orbit.
—Bruce Dorminey, Forbes, 12 Mar. 2025
The scientists used computer models to simulate how CO2 would influence the thermosphere and satellite orbital dynamics under different emission scenarios.
—Margherita Bassi, Smithsonian Magazine, 12 Mar. 2025
While modeling from the 1990s already showed that greenhouse gases trap heat in the lower atmosphere, more recent research determined that the same gases also radiate heat at much higher altitudes — thereby cooling the thermosphere.
—Sharon Udasin, The Hill, 10 Mar. 2025
Cite this Entry
“Thermosphere.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/thermosphere. Accessed 30 Oct. 2025.
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