From Scientific American: The First Stars in the Universe
And now back to your regularly scheduled science.
I've been reading a lot of these "story of a theory" type articles a lot in the past few days. I like them because they're easier to understand as a layperson, which I guess makes sense because they're actually stories that are coming from mainstream science magazines.
Anyway, this article is, just as it says, about the first stars in the universe. How they formed, how long ago, how massive they were. Answers: possibly small variations in density, between 100 and 250 million years after the Big Bang, and between 300 and 1000 solar masses.