When LIGO announced in 2016 that it had discovered gravitational waves, something Albert Einstein predicted in his general theory of relativity, it was a breakthrough moment for astrophysics. The discovery made front-page news, the scientists behind it won the Nobel Prize, and the waveform of two black holes colliding made it onto a t-shirt featured on The Big Bang Theory. Now, with new equipment upgrades, LIGO is likely to make fresh sightings of gravitational waves every few weeks. Joined by the similar Virgo detector in Italy and soon by KAGRA, an underground gravitational wave observatory in Japan, these observations are set to become a regular occurrence. Which is why, for many scientists, the real excitement is still ahead. That’s because gravitational waves aren’t simply a novel consequence of relativity. They’re a revolutionary new way to study outer space without light—to observe things telescopes can’t, and study the invisible parts of the universe. It’s a pretty big deal since only a few percent of the stuff in the universe emits or reflects light, but all of it interacts with gravity. And the light we can see often gets in the way of things we’re actually trying to study. Watch the video above to learn more about how thousands of scientists around the world are looking to use gravitational waves to learn about everything from the Big Bang to some of the biggest events shaping the cosmos. Quartz News is a weekly video series bringing you in-depth reporting from around the world. Each episode investigates one story, breaking down the often unseen economic and technological forces shaping our future. Click here for previous stories.