a unit of length, equal to the mean distance of the earth from the sun: approximately 93 million miles (150 million km). Abbreviation: AU
Why is exciting planet discovery called “Goldilocks,” and what is its actual name?This week, excitement was stoked by the discovery of a “Goldilocks planet” within our astronomical neighborhood. Located about 20 light years away in the constellation of Libra, the exoplanet in question has temperatures ranging from –25 to 160 degrees Fahrenheit , orbits its star from a distance of .146 Astronomical Units (about 14 million miles), and has a mass 3 to 4 times that of …
Five English Words That Are Utterly UniqueRead more in this article about some frequently asked questions and fun facts related to our definitions.
- astronomical frame of reference,
- astronomical refraction,
- astronomical telescope,
- astronomical triangle,
- astronomical twilight,
- astronomical year,
Origin of astronomical unit
First recorded in 1900–05
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a unit of distance used in astronomy equal to the mean distance between the earth and the sun. 1 astronomical unit is equivalent to 1.495 × 10 11 metres or about 9.3 × 10 7 miles
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
A unit of length equal to the average distance from Earth to the Sun, approximately 149.6 million km (92.8 million mi). It is used especially to measure distances within the solar system. Compare light-year parsec.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.