astronomical unit (AU)

astronomical unit (AU)

Approximately equal to the mean earth-sun distance, which is about 150,000,000 km or 93,000,000 miles. Formally, the AU is actually slightly less than the earth's mean distance from the sun (semi-major axis) because it is the radius of a circular orbit of negligible mass (and unperturbed by other planets) that revolves about the sun in a specific period of time.

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Industry/Domain: Astronomy
Category: General astronomy
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