Laura Blecha

At the centers of almost all galaxies lurk black holes — invisible giants. When two galaxies collide, their black holes become a pair doomed to dance around each other. But to merge into one, they must close the gap from vast distances to just kilometers, in the final instant unleashing a burst of gravitational waves.

The James Webb telescope discovered black holes — so named by John Wheeler, and Karl Schwarzschild described them as a light trap — which, just 500 million years after the Big Bang, already weighed more than a million Suns.

A field sown with seeds. Some seeds are large and sprout at the slightest rain; others are finicky, requiring special soil and rare conditions. Which seeds fall into the ground determines what kind of forest will grow years later. Astrophysicists think about the birth of black holes in the early universe in much the same way.