A new time-lapse video from astrophotographer Andrew McCarthy shows the full moon appearing to dance around in the sky … no tricks involved, just the moon wobbling in its orbit around the Earth. Video courtesy of space.com
“You can see how the moon wobbles, showing and hiding parts of its surface, which allows us to see 59% of the illuminated surface from earth.
“That’s called libration and is caused by a couple of factors, but none of them are related to the moon’s rotation.
“That is, the moon is presently in perfect tidal lock with earth, and if it wasn’t for the other factors (orbit inclination, eccentricity, and the observer’s relative position change as the earth rotates), we would always see the same 50% of the moon’s surface.”
Explanation courtesy of Quora’s Fernando Brito, São Paulo State Technological College