Galaxy-formation theory is in peril
Imagine peering into a nursery and seeing, among the cooing babies, a few that look like grown men. That's the startling situation that astronomers have stumbled upon as they've looked deep into space and thus back to a time when newborn galaxies filled the cosmos. Some of these babies have turned out to be nearly as massive as the Milky Way and other galactic geezers that have taken billions of years to form. Despite being only about 800 million years old, some of the infants are chock-full of old stars.