Question

Why do we always see the same side of the moon?

1. The moon rotates at the same speed as the earth rotates.
2. The moon revolves around the earth at the same rate the earth rotates on its axis.
3. The moon rotates on its axis at about the same speed as it revolves around the earth.

Answer 1

Only one side of the Moon is visible from Earth because the Moon rotates on its axis at the same rate that the Moon orbits the Earth – a situation known as synchronous rotation, or tidal locking. The Moon is directly illuminated by the Sun, and the cyclically varying viewing conditions cause the lunar phases. So you're answer is B.

Answer 2

We always see the same Moon, because it takes the same time to rotate once on itself, that in a round around the Earth, a little more than 27 days.

The answer is: 3. The moon rotates on its axis at about the same speed that rotates around the earth.