Noun
a unit of length used for distances within the solar system; equal to the mean distance between the Earth and the Sun (approximately 93 million miles or 150 million kilometers)
Source: WordNetBut all measurements are subject to some degree of error or uncertainty, and the uncertainties in the length of the astronomical unit only increased uncertainties in the stellar distances. Source: Internet
By definition, all NEOs have a closest approach to the Sun ( perihelion ) of less than 1.3 astronomical unit (AU). Source: Internet
In 2012, finding that the equalization of relativity alone would make the definition overly complex, the IAU simply used the 2009 estimate to redefine the astronomical unit as a conventional unit of length directly tied to the metre (exactly main). Source: Internet
In 2006, the International Bureau of Weights and Measures (BIPM) recommended ua as the symbol for the unit. citation In 2012, the IAU, noting "that various symbols are presently in use for the astronomical unit", recommended the use of the symbol "au". Source: Internet
The astronomical unit is too small to be convenient for interstellar distances, where the parsec and light year are widely used. Source: Internet
Depending on the value assumed for the astronomical unit, this yields the speed of light as just a little more than 300,000 kilometres per second. Source: Internet