Does anyone know why Mercury and our Moon do not spin?
enigma said:The Moon orbits the Earth.
You can tell because the side that faces the sun changes: phases of the Moon.
The Moon always has the same side facing us.
Therefore, the Moon rotates at the same rate which it orbits.
This phenomena is called 'tidal lock'.
Chronos said:The moon is mainly non-spheroid because of earth's gravity.
employee #416 said:If I have not been mistaken, I thought we always saw one side of the moon at all times. We have never seen the other half of the moon. Wouldn't this imply that the moon does not spin? If the moon did spin, I'm sure it would be noticeable.
Uh, er, it just dawned on me that I repeated what you had already said :blush:Math Is Hard said:Well, yes. And doesn't this assist in the tidal locking phenomenon?
Welcome to Physics Forums Iron Sun 254!Iron Sun 254 said:It was once believed that Mercury did not spin and I've come across websites that still post this false information. Part of the reason for this misconception is the rotation period and orbital period are in phase so that Mercury rotates 3 times everytime it orbits the Sun twice. Even though it's rotating every other time it reaches the same point in an orbit it's facing the same direction.