Question

Why do we never see the back side of the moon

Answer 1

NASA this week released photographs of the far side of the moon, providing a lunar perspective we rarely get to see. The images were snapped by the Deep Space Climate Observatory satellite, positioned between the sun and the moon with the Earth as its backdrop.

But why is the dark side of the moon, as it’s known, so elusive to the Earthbound?

First, the dark side isn’t really any darker than the near side. Like Earth, it gets plenty of sunlight.

We don’t see the far side because “the moon is tidally locked to the Earth,” said John Keller, deputy project scientist for NASA’s Lunar Reconnaissance Orbiter project. “The moon does rotate, but it rotates at the same speed that it rotates around the Earth.” The moon completes one full rotation on its axis in the time it takes to orbit the Earth. That means the same side is always turned toward us.

Much like a race car drifts when it turns on the curved portions of an oval racetrack, the moon does have a tendency to want to spin faster. Earth’s gravitational pull holds it in place.