How do you prove that in the unimaginably vast universe, certain objects don’t exist?

That’s a question that has plagued scientists studying gravitational waves—ripples in spacetime set off when two massive objects such as black holes swirl together and merge.

For decades, theorists have thought that, ironically, stars in a certain very heavy mass range simply cannot collapse to form black holes.

But gravitational wave astronomers had spotted no evidence of such a “mass gap”—until now.

Analysis of gravitational waves supports theory that some stars explode without leaving behind black holes.