• nBodyProblem@lemmy.world
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    3 days ago

    The BEST way is to use the number of seconds after the J2000 epoch (The Gregorian date January 1, 2000, at 12:00 Terrestrial Time)

    • arc@lemm.ee
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      2 days ago

      ISO 8601 goes from 1582 (Julian calendar adoption) but can go even further with agreement about intention and goes down beyond the millisecond. Not sure why I want an integer from the year 2000 which only represents seconds.

      • nBodyProblem@lemmy.world
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        7 hours ago

        Simplicity and precision.

        Who said it was only measured as an integer? Seconds are a decimal value and many timekeeping applications require higher precision than to the millisecond. Referencing an epoch closer to our current time allows greater precision with a single double-precision floating point number.

        Want to reference something before J2000? Use a negative number.

        It’s independent of earth rotation, so no need to consider leap second updates either unless you are converting to UTC. It’s an absolute measure of time elapsed.