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A petametre (American spelling: petameter) (symbol: Pm) is a unit of length equal to 1015 metres.
Petametres could be used for measuring interstellar distances, but astronomers have been long accustomed to using light-years (about 9.5 petametres) and parsecs (about 31 petametres) instead.
See also: 1 E15 m, SI, metre, SI prefix, Orders of magnitude, light year, parsec
terametre << petametre << exametre