Definition of Light year

  1. profile image44
    Niharika jhaposted 8 years ago

    Definition of Light year

  2. Hmrjmr1 profile image80
    Hmrjmr1posted 8 years ago

    it is the distance light travels in i year,

    According to wikepedia
    A light-year is equal to:

        * exactly 9,460,730,472,580.8 km (about 10 Pm)
        * about 5,878,630,000,000 miles
        * about 63,241.1 astronomical units
        * about 0.306601 parsecs

    The figures above are based on a Julian year (not Gregorian year) of exactly 365.25 days (each of exactly 86,400 SI seconds, totalling 31,557,600 seconds)[4] and a defined speed of light of 299,792,458 m/s, both included in the IAU (1976) System of Astronomical Constants, used since 1984.[5] The DE405 value of the astronomical unit, 149,597,870,691 m,[6] is used for the light-year in astronomical units and parsecs.

    The light-month does not have a precise definition or value, as there is no unique definition of a month in astronomical or SI units: however it may be understood to be approximately one-twelfth of a light-year, in line with the various mundane definitions of the month (hollow month, average Julian month, etc.).