Like a beach chair sagging under a sunbather’s weight, the fabric of spacetime does indeed warp around the mass of the Earth — just as Albert Einstein predicted. And like a swimmer moving through the water, the rotation of the Earth affects the movement of spacetime itself. A gravity probe whose origins date to the era before human spaceflight has finally proved general relativity right, according to NASA.

The Gravity Probe-B measured the geodetic effect, the amount that Earth warps the space and time in which it sits, and frame-dragging, or the extent that Earth’s rotation churns spacetime around with it.