Motion of the stars in the sky
For the same reason we see the stars move from east to west during the night.
When you are on the Northern hemisphere and still facing south, you see the stars move from left to right in a clockwise motion. It would actually be more interesting to turn around and face north, because if you wait long enough, you could see the stars rotate about one point in the sky: the North Celestial Pole (NCP). The stars now rotate in a counter-clockwise direction.
North Celestial Pole:
The stars rotate counter-clockwise.
Mouse over either image to see how you can find the Celestial Pole (Images generated with Skymap Pro).
When you are on the Southern hemisphere, it is again the opposite. Facing north you will see the stars move in a counter-clockwise direction and facing south, you will see the stars rotate about the South Celestial Pole (SCP) in a clockwise direction.
South Celestial Pole:
The stars rotate clockwise.
If you live close to the equator, either of the two celestial poles will be very low in the sky, or even invisible, but you will still see the stars move clockwise or counter-clockwise, depending on whether you face south or north.
Answer to question on previous page:
From the map you can see that North is up.