why does the same side of the moon always face the earth

The same side of the Moon always faces the Earth because of a phenomenon called tidal locking. This means that the Moon rotates on its axis at exactly the same rate that it orbits the Earth. As a result, it keeps the same hemisphere facing Earth at all times, making it appear as though the Moon does not spin from our perspective. Tidal locking happens because the Earth's gravitational pull on the near side of the Moon is stronger than on the far side. This gravitational difference caused the Moon to deform slightly and eventually settle into a rotation period synchronized with its revolution around Earth. If the Moon tried to rotate faster or slower, Earth's gravity would create a torque pulling it back into alignment, maintaining the same face toward Earth. In essence, the Moon completes one full rotation on its axis for every orbit it makes around Earth, which is why we always see the same side—the near side—and the opposite side is called the far side, which we never see from Earth. The Moon does have day and night cycles on both sides due to the Sun's illumination, so the "dark side" term is misleading.