Definition of astronomical unit in English: astronomical unit
(also AU )
noun Astronomy A unit of measurement equal to 149.6 million kilometres, the mean distance from the centre of the earth to the centre of the sun.
Example sentences
‘Today the distance between the Earth and sun, known as an astronomical unit, is accurately measured by radar.’ ‘Typical distances from the Sun are 10,000 astronomical units, and typical orbital periods are on the order of 1 million years.’ ‘These stars are generally separated by distances of several astronomical units or more.’ ‘Because the relative distances to the planets were well known, a definitive astronomical unit allowed the actual distances to be calculated.’ ‘Even at its closest, Sedna comes no nearer to the Sun than 76 astronomical units, each AU equaling the average distance of the Earth from the Sun.’ ‘Bodies that formed from the Sun out to a distance of about 2.5 astronomical units are primarily rocky and metallic.’