| The astronomical unit, or AU, is the average distance between the Earth and Sun. It is a convenient unit to use when expressing distances within the solar system. The AU, as defined in the IAU (1976) system of constants, is equal to 149 597 870 km.
In terms of other units, 1 AU is equal to;
| 92 955 807 | miles |
| 499.004 782 | light seconds |
| 1 / 63 241 | light-years |
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