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Year as

days, length and light

YEAR (AS, ge'ar, pry-, Goth. 0110. jar, Ger. Jahr, year; connected with °Church Slay. pa, horn, season, spring, hour, Al. yard. year). In general, a space of time equal in length to the period occupied by the earth in Completing a circuit of its orbit around the A-tronomers distinguish several dif ferNit kinds of years. The tropical year is the year of ehronologists and of the calendar (q.v.), and is defined as the interval of time between two successive passages of the sun through the vernal equinox (q.v.). Its length is 365 days 5 hours 48 minutes and 46 seconds. The sidereal year is the actual period of the earth's orbital revolution, and differs from the tropical year on account of the precessional motion of the equinoxes themselves. (See PRECESSION.) It is 365 days 6 hours 9 minutes 9 seconds in length. The anomalistic year is the time elapsing be tween two successive returns of the earth to its perihelion (q.v.) point. It is a little longer than

the sidereal year, on account of the motion of the earth's perihelion. (See PERTURBATIONS.) Its length is 365 days 6 hours 13 minutes 43 seconds. The light year is a unit of linear measure, used by astronomers in stating the distances of the fixed stars. (See STAR.) It is the linear space traversed by light in one year, and as light moves at the rate of about 136,600 miles per second. the light year furnishes a linear unit large enough to measure even the vast cosmic distances of interstellar space. Bissextile, or leap-year (q.v.), is a calendar year in which the ordinary number of days has been arbitrarily increased by one, making it contain 366 days instead of 365. The commencement of the year among the Jews and Mohammedans has no fixed position in relation to the sun's course or the seasons, it be ing a lunar year. See CALENDAR.