Theory of Relativity in Space: Latest science, tests and images

A massive cosmic object can act like a lens, magnifying and warping the images of background bodies. Learn all about this "gravitational lensing" phenomenon in the third episode of "We Don't Planet."

The uppermost layer of the sun is slowing down and astronomers think Einstein's special relativity could be to blame.

Black holes twist space like taffy and create vortices of gravitational force, a new study suggests. The discovery solves a 30-year-old mystery about black holes.

Former NASA astronaut Scott Kelly's historic one-year mission aboard the International Space Station made his identical twin Mark an even older brother, by about 5 milliseconds.