Why do we always see the same side of the Moon from Earth?
- The Moon rotates exactly once for every orbit it makes around Earth
- The Moon does not rotate at all
- The far side is permanently dark, so it can never be seen
- Earth's shadow constantly hides the far side
Why A? And why not the others?
Correct answer: A. The Moon rotates exactly once for every orbit it makes around Earth
The Moon spins on its axis in the same 27.3 days it takes to orbit Earth, a state called synchronous rotation caused by tidal locking — Earth's gravity gradually braked the Moon's spin until the two motions matched. The idea that the Moon does not rotate is the classic trap: if it truly never turned, we would see every side of it over a month. Calling the far side 'permanently dark' repeats another myth — it receives just as much sunlight as the near side, only during our lunar night. Earth's shadow, meanwhile, touches the Moon only during brief lunar eclipses.
Source: NASA Science: Tidal Locking (science.nasa.gov/moon/tidal-locking/)