Status Updates From The First Three Minutes: A ...

Excellent, as always with Weinberg. He's also very honest with what is known and what is just speculative .

"This is not to say that we actually understand how galaxies are formed. The theory of the formation of galaxies is one of the great outstanding problems of astrophysics, a problem that today seems far from solution."

The earliest supernova detected in a galaxy NOT the Milky Way was in 1885 in the Andromeda Galaxy.

So far so good. Although he makes one small error. He says "electrons, positrons, neutrinos and photons were continually being created out of pure energy." He knows better. There's no such thing as pure energy. There are only particles (electrons, etc.) and *they* have energy.