Sorry, what are timeline separated events? Or is that timelike?
For galaxy formation you also need some manner of getting rid of excess kinetic energy. This occurs mainly by radiating it away. However, that is an entirely different topic for which you should start a new thread if you want to discuss it in detail.
I would close the book and not reopen it. Sell it if you can. It is an entertainment book, not an educational book.
As stated several times, the last part is plain wrong. If there is a reference frame, where A and B are simultaneous, then the events are spacelike separated and cannot be causally connected. You can always find reference frames where A is before B (wrt. the coordinate time of these reference frames) and other frames, where B is before A (again wrt. the coordinate time of these reference frames). Better look for a SRT book that is right!
I was going to say that, except the new owner might not read Physics Forums...
Unfortunately, as others have commented, this makes the problem we see worse, not better. The standard answer in such situations, as has already been said, is that pop science books are not acceptable sources.
At this point the OP has been sufficiently addressed. Therefore, the thread is closed.
Please start a separate thread if you want to discuss this. But, as we have already seen, the book you are reading is not a good source, so I would not trust its explanations. You should look for an actual cosmology textbook. Liddle's An Introduction to Modern Cosmology would be one possibility.
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