The moon does not have a dark side; it has a near side, which we can see from Earth, and a far side, which we cannot. One lunar hemisphere always faces toward us, the other always faces away. It’s due to the moon’s synchronous rotation as it orbits the Earth. Tides on Earth slow the moon’s turning so that it rotates only once for each orbit around the Earth—called tidal locking. I only grasp this concept by lifting pen from paper and orbiting it around my fist, while rotating the pen a single time during that orbit. Result—the pen’s clip always faces my fist.
Earth
as center of the universe—
then Copernicus
Assuming the far side of the moon is dark because it faces away from us is like suggesting we are the source of light rather than the sun. In fact, all aspects of the moon receive the same amount of sunlight. When we see a half-lit moon, half of the other side is also lit. A crescent for us—a gibbous brightness on the flip side. New moon—the far side is totally illuminated.
trying to think
in three dimensions
inside my head it’s dark