[Geezer (OP)]

How long does it take the Earth to rotate through 360 degrees?

[syhprum]

The time of one rotation of the Earth known as the sidereal day day is approximately 23 hrs, 56 minutes, 4.091 seconds.
It varies a little year on year by a few milliseconds due to tectonic and ocean movements. 

[Geezer (OP)]

The time of one rotation of the Earth known as the sidereal day day is approximately 23 hrs, 56 minutes, 4.091 seconds.
It varies a little year on year by a few milliseconds due to tectonic and ocean movements. 

Well, that topic didn't last too long!  []

Presumably, the Earth rotates 366.25 (approximately) revolutions in one year rather than 365.25 (approx) as I had always imagined, until I actually started to think about it.

[Geezer (OP)]

We might tend to think the Moon does not rotate, but I suppose it really does rotate once per orbit of the Earth.

[syhprum]

It is very pleasent to get a simple factual question to answer, I get cheesed off by all the stuff about General relativity, blackholes etc.

I could not find anyone that quoted the length of the sidereal day on the Moon so I had to do the laborious Babylonian arithmetic and I make it 27 days, 5 Hrs, 55 Minutes and 46.7 sec

[Geezer (OP)]

I could not find anyone that quoted the length of the sidereal day on the Moon so I had to do the laborious Babylonian arithmetic and I make it 27 days, 5 Hrs, 55 Minutes and 46.7 sec

How does Babylonian arithmetic work? That might be an interesting topic.

BTW, Is there any connection between the number of degrees in one revolution (360) and the number of days in a year, or is it just a coincidence that they are not very far apart?

[Soul Surfer]

Yes there is a relationship the Babylonians thought there was about 360 days in a year and one degree in the sky is the distance travelled by the sun against the stars in a day.  they liked round numbers and a system based on 60