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astronomical unit
noun
: a unit of length used in astronomy equal to the mean distance of the earth from the sun or about 93 million miles (150 million kilometers)
Examples of astronomical unit in a Sentence
Recent Examples on the Web
The Solar Orbiter ventures between 1 astronomical unit, where the Earth is, and 0.3 astronomical units, a little closer to the Sun than Mercury.
—Yeimy J. Rivera, Discover Magazine, 6 Sep. 2024
Based on their models, its reach would have shrunk to 0.22 astronomical units—or just about a fifth of the distance between the Earth and sun—leaving our planet outside the star’s protective field.
—Christian Thorsberg, Smithsonian Magazine, 14 June 2024
It's probably located somewhere between 500 and 600 astronomical units from the Sun.
—Chas Newkey-Burden, The Week Uk, theweek, 19 Apr. 2024
At its orbital distance of 1 astronomical unit from the sun, Earth receives about 1.4 kilowatts per square meter from sunlight.
—Karl Schroeder, IEEE Spectrum, 24 Feb. 2024
See all Example Sentences for astronomical unit
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'astronomical unit.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Word History
First Known Use
1848, in the meaning defined above
Time Traveler
The first known use of astronomical unit was
in 1848
Dictionary Entries Near astronomical unit
Cite this Entry
“Astronomical unit.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/astronomical%20unit. Accessed 2 Nov. 2024.
Kids Definition
astronomical unit
noun
: a unit of length used in astronomy equal to the average distance of the earth from the sun or about 93 million miles (150 million kilometers)
More from Merriam-Webster on astronomical unit
Britannica.com: Encyclopedia article about astronomical unit
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