exosphere

noun

exo·​sphere ˈek-sō-ˌsfir How to pronounce exosphere (audio)
: the outer fringe region of the atmosphere of the earth or a celestial body (such as a planet)
exospheric adjective

Examples of exosphere in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
These elements are linked to both processes, indicating that both micrometeoroids and solar wind added to the Moon’s exosphere. Jonathan O’Callaghan, Discover Magazine, 21 Oct. 2024 So, the question remains how Titan maintains its thick atmosphere over timescales of billions of years and why other such icy moons appear to only have thin exospheres. Bruce Dorminey, Forbes, 10 Oct. 2024 But the ring could not last: both the pull of gravity and the drag of Earth’s exosphere, which extends more than 6,000 miles into space, would eventually pull the rubble down to the surface, eliminating the ring. Jeffrey Kluger, TIME, 18 Sep. 2024 Astronomers have for decades been aware of the delicate atmosphere surrounding the moon that is so thin and fragile that it's better referred to as an exosphere. Eric Lagatta, USA TODAY, 12 Aug. 2024 See all Example Sentences for exosphere 

Word History

Etymology

exo- + -sphere

First Known Use

1949, in the meaning defined above

Time Traveler
The first known use of exosphere was in 1949

Dictionary Entries Near exosphere

Cite this Entry

“Exosphere.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/exosphere. Accessed 21 Nov. 2024.

Kids Definition

exosphere

noun
exo·​sphere ˈek-sō-ˌsfi(ə)r How to pronounce exosphere (audio)
: the outermost region of the atmosphere of the earth or a planet

More from Merriam-Webster on exosphere

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!