30 days for the moon to orbit the earth
365 days for earth to orbit the sun
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The above are standard, rough estimates for these basic periods. None of them is completely accurate. 24 hours is a day of UTC (Co-ordinated Universal time), or standard time. This used to be called Greenwich Mean Time.
A day i.e 24 hours, is time of a single rotation of planet Earth with respect to the sun.
But a 360-degree rotation about its axis happens every 23 hours 56 minutes and 4 seconds, roughly, and this period is called the Sidereal Day, so yes, one sidereal day equals one full 360o rotation of the earth.
The difference between sidereal days and solar days is because, in addition to spinning on its axis, the earth is also slowly moving/revolving around the sun. So when it spins once in relationship to itself and to, say a distant star in outer space directly above the equator, i.e. 360o, its position has also moved slightly round the sun. So it has to spin a round little bit more for the sun to be directly overhead, or at its highest point again. So, in approximate terms, it spins 1 and 1/365ths of a 360o rotation every 24-hour day. And 24 divided by 1 and 1/365 = 23.9344 hours, which is 23 hours, 56 minutes and 4 seconds, one sidereal day.
The moon's orbit around the earth takes about 27.3 days; the cycle of moon phases takes about 29.5 days. The orbit and the cycle of phases are not the same length of time.
A year is 365.2422 '24 hour' days, approximately. Anyone familiar with the need for 'leap days' realizes that 365 days is just a rough workable estimate, and that a leap day has to be inserted periodically to align our calendar with the solar year, i.e. one complete movement of the earth around the sun.
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it takes the earth 24 hours to rotate once.
Emdrgreg