Whilst theres a side we cant see, that doesnt make it dark. Tidal forces from the Earth have slowed the moon to the point that it rotates on its axis at the same speed that it takes for it to orbit the Earth, so the same side of the Moon is always facing us a phenomenon known as tidal locking. The other side of the Moon that we cant see has been referred to as the dark side of the moon as it appeared to receive no light but that is an egotistical point of view. The side that we do not see receives as much light as the side we do. During a full Moon, the side of the Moon facing us is entirely bathed in sunlight, whilst during the rest of the lunar period only a portion of the side we see is lit up. However, that doesnt mean less light is falling on the Moon. The rest falls on the dark side more appropriately referred to as the far side. Until 1959, when the Soviet Unions Luna 3 space probe captured a photograph of the far side, nobody had ever known what it looked like. The dark side of the Moon is therefore not about an absence of light, but about what we just cant see. Perhaps thats what Pink Floyd was referring to after all.
