astronomical unit

noun

Definition of astronomical unit 

: 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

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At this week’s pass, the asteroid will be about .07 astronomical units or about 6.5 million miles away — the equivalent of about 30 trips between our pale blue planet and the moon. Blaine Friedlander, Washington Post, "The biggest meteor shower of the year peaks tonight. Here’s how to watch.," 13 Dec. 2017 Gliese 710 will be about 16,000 astronomical units away from the sun. Jason Daley, Smithsonian, "2.8 Million Stars Sparkle in This Incredible Image of the Milky Way," 6 Sep. 2017 For instance, the object takes 1,100 earth years to orbit the sun in an elliptical orbit that brings it as close as 38 astronomical units (the distance of the earth to the sun) and as far as 180 AUs. Jason Daley, Smithsonian, "Meet DeeDee, the Solar System’s Newest Dwarf Planet (Maybe)," 14 Apr. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'astronomical unit.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of astronomical unit

1848, in the meaning defined above

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The first known use of astronomical unit was in 1848

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Britannica.com: Encyclopedia article about astronomical unit

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