Mercury's spin and its orbit around the Sun are tied to each other in a unique arrangement. According to a set of calculations, random asteroid impacts may have aided the planet's evolution into the ...

The Moon takes the same time (27.3 days) to rotate once on its axis as it takes to orbit the Earth. This is called synchronous rotation. Does this mean we always see the same face of the Moon, and ...

Have you ever wondered why we only see one side of the moon when we look at it from Earth? We would expect to see the other side of the moon because it is a rotating sphere, but this is not the case.