# Rotation and relativity

When a planet is spinning around its own axis, it has an effect on the trajectory of its satellites. I believe it is called frame dragging.

Spin increases the kinetic energy of an object, contributing to its mass-energy, but some other effect must come into play as well.

How does one differentiate between spin and orbit velocity?

What is the effect of the spin? Lets say that Earth suddenly started spinning faster, what would happen to the moons trajectory?

-
I don't understand why this was downvoted? I just want to know what the observed physical effect of various rates of spin would be, and what causes it. – frodeborli Jan 10 '14 at 10:27
– Gerald Jan 13 '14 at 0:34
It isn't actually clear what question you are asking. Are you asking what causes frame-dragging? ('...but some other effect must come into play...'). Are you asking how to differentiate between spin and orbit velocities? Are you asking what the observable effects are if a body had a different rate of spin? – Jeremy Apr 5 '14 at 20:42

The moon's rotation plane would precess (more) in the same direction as Earth's rotation, if the Earth spun faster.

-
Is the increased precession the only result of increased mass (due to higher kinetic energy)? – frodeborli Apr 2 '14 at 11:16
So, an object that is spinning does not have a higher kinetic energy? And through E=mc^2 you don't get an increase in mass-energy as a result of spin? I will accept your answer if you answer that by editing your answer. :) – frodeborli Apr 3 '14 at 10:43
While the answer does not claim to state that this is the only effect, which I would rely on others to comment on (eg Moon's trajectory, what else besides increased mass contributes to frame-dragging), the answer, I think, stands as an answer to the question about what happens if the Earth spun faster. – Jeremy Apr 5 '14 at 20:38