The Power of the Dark Side
The descriptor "dark side" is problematic. It seems to suggest that shadows perpetually cloak the surface of one side of the moon. It's easy to imagine a dividing line between the light side and the dark, and that by crossing this line you pass into the side of the moon we never get to see from Earth. But that's simply not true.
While it's true that some part of the moon is dark at any particular time, it's not always the same part. That's because, like Earth, the moon has a daytime and a nighttime. So if you were to set up camp on the moon and stay put, you would eventually see the sun rise and fall. You'd experience both day and night.
Since the dark side of the moon shifts as the lunar day progresses, it's more accurate to say that the moon has a day side and a night side, just like the Earth. The day side is the side currently receiving sunlight, while the night side faces away from the sun. What does this have to do with the side we see when we look at the moon from Earth? That's where things can get confusing. The side of the moon we see is sometimes the day side, and sometimes the night side. It all depends on when during the lunar day we look at the moon.
A more accurate term to describe the side of the moon we see is the near side. The side opposite the near side is the far side. The near side will always face toward us, and the far side will always face away. This is true even on the opposite side of the Earth. If you were to fly from America to Australia just to get a look at the moon down there, you'd see the same features you're familiar with back home.
Both the near side and the far side of the moon have a day and a night. Both receive sunlight at certain points of the moon's orbit around the Earth. We just can't see the far side of the moon, even when the sun is shining on it, because the far side always faces away from us.
So why do we only see one side of the moon from Earth, and what do the phases of the moon have to do with it? Keep reading to find out.