[Deo volente]

I’m just a dumb layman, but if the first lights were just coming on at that time, how are there already fully formed galaxies full of mature stars with heavy elements?

[Red Badger]

The stars were of hydrogen and the galaxies were globular............

[Renfrew]

“I’m just a dumb layman, but if the first lights were just coming on at that time, how are there already fully formed galaxies full of mature stars with heavy elements?”

To answer:

1) stars form when enough dust gathers in one place. Usually that process leads to many stars forming at once. So we get galaxies pretty early.

2) One of the things that is interesting about these galaxies is they are missing the heavy elements. Almost all primordial hydrogen and helium without the wider collection we see in our stars.