Rahul Kannan

The 'Sleepy' galaxy in the early universe furiously gave birth to stars, but after 300 million years it fell asleep. A record-breaking hydrogen dip in its glow showed that not all bright early galaxies become giants—some doze off and turn into dwarfs.

For decades astronomers puzzled over mysterious anti-correlations of light elements in globular clusters. New research based on high-resolution cosmological simulations shows: the chemical anomalies could have arisen long before the birth of the cluster's first stars—in giant gas clouds. This scenar