Why the Sky Moves: Practice Problem Solutions

1. Earth spins west to east, which makes the sky appear to turn east to west.

2. About 15 degrees (360 divided by 24).

3. A circumpolar star is close enough to the celestial pole that it never sets, but circles it all night. Examples: Polaris, the Little Dipper, Cassiopeia (from Alabama).

4. In summer the Sun is in the part of the sky where Orion is, so Orion is above the horizon only in daytime and can't be seen. In winter the Sun is elsewhere and Orion shows in the night sky.

5. About 4 minutes earlier each night, because Earth moves along its orbit, so we have to turn a little more than 360 degrees to face the same star.

6. About 23 hours 56 minutes.

7. At the north celestial pole, close to Polaris.