synchronous rotation

Synchronous rotation in astronomy refers to a phenomenon where a celestial body, like a moon, rotates on its axis at the same rate it orbits another body. This results in the same side of the celestial body always facing the primary body.12

This occurs due to tidal friction. Gravitational forces between two bodies cause tidal bulges. If the orbiting body rotates faster than its orbit, the tidal bulge is pulled ahead, creating a torque that slows the rotation. Conversely, if it rotates slower, the bulge lags, and the torque speeds up rotation. Over time, this process leads to synchronous rotation, where the rotation period matches the orbital period.12

The Moon is a prime example, always showing the same face to Earth. This state is considered a stable end point for tidal evolution in many celestial body pairs within the solar system.23