Sun warping space-time, illustration. At right of the Sun is the Earth. Space-time is represented here with a green grid, which is warped as described in Einstein's theory of General Relativity. The gravity of massive bodies warps space-time, causing stars and planets to move along paths determined by this geometry. Einstein's theory also predicted the existence of gravitational waves, ripples in space and time that move at the speed of light and which are created when massive bodies accelerate through space and time. Image published in 2016.