Every now and again, I imagine some alien civilization out there gets snuffed out by a physics experiment gone wrong.
What followed the start of the first universe?
A monstrous fireball that inflated about 100 million light years in a few hours.
Create that universe and you snuff out every living thing and every star within 100 million light years (which would be thousands of galaxies.)
Ideally, its expansion wouldn't displace space or time or matter in our own universe, but create its own.
Hmm..I've seen people not be able to get past the idea that the big bang was expanding into something that was already there, before, and I can't figure out how to explain what it's actually saying.
You have to completely empty your mind of the idea of "space" as this permanent, empty, unchanging thing. If a new universe expands in a big bang, it's not expanding "into" anything - it doesn't swallow up any pre-existing stars or galaxies. Spacetime ITSELF is expanding.