Astronomers puzzled by little red galaxies that seem impossibly dense

Strangely bright galaxies spotted by the James Webb Space Telescope (JWST), called “little red dots”, may have more stars packed into them than any other galaxies we know of. The density appears so high that it’s unclear how the stars even survive without crashing into their neighbours, challenging astronomers’ best ideas of how galaxies grow.

Shortly after JWST started searching the extremely distant universe in 2022, astronomers started to see extremely bright and red, but apparently tiny, galaxies, which they called little red dots…