There’s been a lot of chatter recently suggesting that physicists may have finally found gravitational waves. It would prove to be an incredibly important discovery—but if you’re still not quite sure why, this explanation is probably the most straightforward one you’ll find.
Jorge Cham of PhD Comics decided to take a stab at explaining what gravitational waves are and why finding them in the wild would be so important. He’s done a great job.
If video doesn’t do it for you, you can also read a comic strip version over on PhD Comics.