Tidal_Lock

Tidal Lock

Tidal lock occurs when an object completes a single rotation in the same time that it takes to orbit another object. The causes the same surface of the first object to remain facing the second object.

Earth's moon exhibits tidal lock, which is why the same "side" always appears to face Earth. In the case of the moon, this means there is a small portion of the surface that is never seen from anywhere on Earth, ever.

Town World's moon is also tidally locked to Town World, but Town World itself is tidally locked with respect to the star it orbits. This means there is no day or night as on Earth, just a periodic dimming and brightening of the average amount of light for any given location due to the shape of the orbit and frequent eclipses.