Einstein's theory of relativity predicts that large rotating objects should drag space and time around themselves as they turn. The first direct evidence of this phenomena was announced in March 1998 by an international team of NASA and other scientists, who discovered that Earth does indeed drag time and space around itself as it rotates. The researchers detected this effect, called "frame-dragging," by precisely measuring shifts in the orbits of two Earth-orbiting satellites (LAGEOS I and II). The team found that the plane of the orbits of the two satellites shifted about six feet (two meters) per year in the direction of Earth's rotation.

Frame-dragging is not unlike the effect of a bowling ball spinning in molasses. As the ball spins, it pulls the molasses around itself. Anything stuck in the molasses will also move around the ball. Similarly, as Earth rotates, it pulls nearby space and time around itself. This pull shifts the orbits of satellites near Earth.