<P> The Julian year , as used in astronomy and other sciences , is a time unit defined as exactly 365.25 days . This is the normal meaning of the unit `` year '' ( symbol `` a '' from the Latin annus ) used in various scientific contexts . The Julian century of 7004365250000000000 ♠ 36 525 days and the Julian millennium of 7005365250000000000 ♠ 365 250 days are used in astronomical calculations . Fundamentally , expressing a time interval in Julian years is a way to precisely specify how many days ( not how many `` real '' years ) , for long time intervals where stating the number of days would be unwieldy and unintuitive . By convention , the Julian year is used in the computation of the distance covered by a light - year . </P>
<P> The Julian year , as used in astronomy and other sciences , is a time unit defined as exactly 365.25 days . This is the normal meaning of the unit `` year '' ( symbol `` a '' from the Latin annus ) used in various scientific contexts . The Julian century of 7004365250000000000 ♠ 36 525 days and the Julian millennium of 7005365250000000000 ♠ 365 250 days are used in astronomical calculations . Fundamentally , expressing a time interval in Julian years is a way to precisely specify how many days ( not how many `` real '' years ) , for long time intervals where stating the number of days would be unwieldy and unintuitive . By convention , the Julian year is used in the computation of the distance covered by a light - year . </P>
according to science how many days are in a year
according to science how many days are in a year
365.25 days
365.25 days