Shiyang Hu

In 2019, the Event Horizon Telescope gave humanity the first image of a black hole's shadow. Since then, astrophysicists have dreamed of more: seeing how matter moves in the very funnel of spacetime. One of the mysteries is chaos.

A black hole is not just a dark sphere in space. If there is gas and dust nearby, they swirl into a flat, glowing disk that gradually falls inward. This disk acts like a lamp, illuminating the hole itself, and against the bright background you can see its shadow — a dark silhouette with sharp edges. But what if the disk is not flat but torn into pieces?

A black hole pulls in anything that gets too close. But if you toss in not one object but a pair, one of them can fly back out, carrying off some of the hole's rotational energy. This trick, devised by Roger Penrose in 1969, works only because a black hole has a horizon — a boundary beyond which nothing returns. Now it turns out the horizon isn't necessary.