> The earth rotates on it's axis once in 24 hours with respect to the sun. But with respect to the background stars, it is a little less. This is called a siderial day. Trusting my memory on that, I think it is about three minutes shorter than a solar day.

The Earth's rotation is about 23 hours, 56 minutes, 4.091 seconds if I remember rightly. Is that spelt siderial or sidereal? I can never remember.

Beasty