How does long it take the earth rotate on its axis?

Answer 1

The period is 24 hours, governed by the Sun rising and setting. But this is a trick question because during that 24 hours, the Earth has gone round its orbit a little so it has to rotate for four extra minutes each day to get to noon with the Sun at the same place in the sky.

The period relative to the stars is 23 hours 56 minutes, so our 24-hour day makes all the stars rise and set four minutes earlier each day.