light-year

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light-year

light-year in astronomy, unit of length equal to the distance light travels in one sidereal year . It is 9.461 × 10 ¹² km (about 6 million million mi). Alpha Centauri and Proxima Centauri, the stars nearest our solar system, are about 4.3 light-years distant. See also parsec .

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light-year

World Encyclopedia | 2005 | Â© World Encyclopedia 2005, originally published by Oxford University Press 2005. (Hide copyright information) Copyright

light-year Unit of astronomical distance equal to the distance travelled in free space or a vacuum by light in one tropical year. One light-year is equal to 9.4607 × 10¹² km (5.88 × 10¹² mi).

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