The Dark Side of the Moon

Why you may ask, is the name of this novel "The Dark Side of the Moon"? The back side of the Moon is not dark, it receives as much sunlight as the front side does. The term "dark" is often used in Science to denote our lack of knowledge, such as in Dark Matter and Dark Energy. Because the moon's front side always faces earth until recently no human has been able to see the Moon's backside. That is until 1979 when t he Soviet space probe Luna 3 took the first grainy photographs and in 1968 the Ap