The Moon is seen to keep one face toward Earth at all times. If viewed from a point directly above the plane of the planetary system, how does it have to rotate to maintain this alignment?
A) The moon must rotate once per day to maintain its direction toward Earth.
B) The moon must not rotate at all because we always see the same face from Earth.
C) The moon must rotate once per year as Earth and the Moon orbit the Sun together.
D) The moon must rotate once per month, or once per orbit around Earth.

Question

Quizplus · Accepted Answer

The Moon rotates on its axis once per orbit around Earth, which is approximately once per month. This synchronous rotation keeps the same hemisphere of the Moon facing Earth at all times.

The Moon Is Seen to Keep One Face Toward Earth