Here is more background on how this theory came to be:

Based on his predictions, scientists confirmed galaxies warp light with their gravity, photons get time dilated when they pass near the sun, and clocks that travel at high speeds experience less time than clocks on Earth.

By watching the extremely regular energy blasts coming from pulsars, astronomers track exactly how quickly they’re radiating their energy away due to gravitational waves. So far, all the observations perfectly match the predictions of relativity. We just haven’t detected those gravitational waves directly… yet.

So, good news! Assuming the physicists and Einstein are right, we should see the detection of a gravitational wave in the next few decades, wrapping up a series of predictions about how insanely strange our universe behaves.

We hope you are intrigued and enjoy the video!

thanks to phys.org for the great info

thanks to NASA for the pic