Look a little closer
The Moon keeps nearly the same pattern facing Earth not because it fails to rotate, but because it rotates exactly once during each orbit. One spin and one trip around Earth take the same amount of time, so the same hemisphere remains pointed toward us.
This state is called synchronous rotation, a form of tidal locking. Imagine walking in a circle around a friend while continuously facing them. To complete the circle without turning your back, your body must also make one full rotation.
The young Moon probably spun faster. Earth's gravity slightly distorts the Moon away from a perfect sphere. When the direction of that tidal bulge did not line up with Earth as the Moon turned, gravity exerted a torque that pulled it toward alignment.
Repeated flexing inside the Moon dissipated rotational energy as heat, gradually slowing the spin. Once one rotation matched one orbit, the bulge could stay nearly aligned with Earth and the system settled into a stable configuration.
We can nevertheless see a little more than one-half of the lunar surface over time. The Moon's elliptical orbit and tilted axis produce apparent nodding and rocking called libration. Taken together, these motions expose about 59 percent of its surface to observers on Earth.
The lunar far side is not a permanently dark side; it experiences daylight and night like the near side. The familiar face in our sky is a record of gravity synchronizing the Moon's spin with its orbit over a very long time.
