Danilo Marchesini

The James Webb Space Telescope looked back to a time when the universe, just after the Big Bang, was only a billion years old, and found the 'Sleepy' galaxy. Unlike its neighbors, which shone with young stars, it looked tired and dim.

The Bullet Cluster is a cosmic collision site where two vast clouds of galaxies, gas, and invisible matter slammed into each other. When light from distant stars passes near such a cluster, gravity bends its path like a lens. Astronomers study these distortions to work out where the mass is hiding.

The first two billion years after the Big Bang were an era when the universe resembled a boiling construction pit. Dark matter clumped the gas together, igniting the first stars. It seemed there simply wasn't enough time to assemble massive elliptical galaxies—'dormant' stellar metropolises — from this raw material.