Lv 4
Nick asked in Social ScienceOther - Social Science · 12 months ago

Astronomically speaking : what is a "week"?

A "year" is an orbit of the sun,

A "month" is an orbit of the moon.

A "day" is a revolution of the earth.

What is a "week"?

7 Answers

  • 12 months ago
    Favorite Answer

    From "":

    The seven-day week originates from the calendar of the Babylonians, which in turn is based on a Sumerian calendar dated to 21st-century B.C. Seven days corresponds to the time it takes for a moon to transition between each phase: full, waning half, new and waxing half. Because the moon cycle is 29.53 days long, the Babylonians would insert one or two days into the final week of each month.

  • zipper
    Lv 6
    12 months ago

    A week is a measure of time set by mankind to keep perspective time with, this has nothing to do with Astronomic other than a man made measure of time as are months years, hours and minutes!

  • 12 months ago

    Originally had religious roots the time to create the universe, then the smarter sort back in bablonian times based it on the 4 phases of the moon. The calendar changed a bit with Cesar but the periods remained the same.

    Why new moon to new moon is not exactly a month and week no longer exactly a quarter phase of the moon.

    Just arbitrary but related to the earth and moon movements. It could be changed to any cocamamy sceme one chose.

  • Lôn
    Lv 7
    12 months ago

    A week is simply 7 days. There is no astronomical significance.

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  • Nancy
    Lv 7
    12 months ago

    A week is approximately one-quarter of a lunar cycle, each lunar cycle originally being a month, making originally 13 months in a year and why there are actually 13 zodiacal signs. In ancient times, charting these lengths of time was far less precise. Anyway, the peoples of Ancient Rome, Ancient Greece, Ancient Egypt, they all needed to have calendars that jibed with each other for reasons of commerce, so a calendar based on the lunar cycle was devised, but each unit of time over a single day being 28 days was too long to be useful, whereas 28's other divisors, four and two, were too short to be useful, thus landing them on seven.

  • 12 months ago

    Seven days as a rule

    Attachment image
    Source(s): Weak in the Force is this one Skippy
  • 12 months ago

    An arbitrary chunk of days invented by humans.

    There's no logical reason why it couldn't be six days or eight, it's just tradition. It would be interesting to know where and why that tradition first started but I don't.

    Edit: A continuous seven-day cycle that runs throughout history paying no attention whatsoever to the phases of the moon was first practised in Judaism, dated to the 6th century BC at the latest.

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