Frame-dragging

Frame-dragging is an effect on spacetime, predicted by Einstein's general theory of relativity, that is due to non-static stationary distributions of mass–energy. A stationary field is one that is in a steady state, but the masses causing that field may be non-static, rotating, for instance. More generally, the subject that deals with the effects caused by mass–energy currents is known as gravitomagnetism, which is analogous to classical electromagnetism.
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