A Year in Mercury

How long is a year on Mercury?
Mercury has the shortest year in the Solar System. It is about 88 Earth days long.

It used to be believed that the same side of Mercury always faced the Sun. In order for this to be true, Mercury would have to take the same amount of time to rotate (spin around) as it does to circle the sun. Through careful observation we now know that Mercury's rotation is somewhat faster than its orbit. Because of the way the orbit and rotation work together, on Mercury, a day is actually almost twice as long as a year.