[Beltiras]

I know what people mean when they say "dark side of the moon" but it always bothers me. There is no "dark side" to the moon. The picture that got stuck in my head was seeing the moon transit the earth: http://www.abc.net.au/science/articles/2015/08/21/4296866.ht...

Beautiful picture.

[Zenka]

Isn't it the dark side of the moon, since spacecraft passing behind the moon go 'dark'; out of radio contact since the moon blocks radio signals?

On the other hand: it's the side of the moon that never receives earthshine. So it's dark in that sense.

[sdenton4]

Which is a great reason to get a dumb little cubesat comms relay into lunar orbit...

[Beltiras]

I hadn't thought about that sense of the phrase. That makes total sense.

[dnautics]

Its the side of the Moon that's dark when it faces the earth?

[Beltiras]

When people say "dark side of the moon" they are almost exclusively speaking about the side that faces away from Earth.

[dotancohen]

The moon is tidally locked: rotates at the same speed that it resolves around the Earth. Therefore the same side always faces the Earth, modulo liberation.