Astronomy is no longer about what we can see. Here’s how we’re sensing the invisible universe.

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.