[ben_w]

Kinda but different scale, the CMB era universe was about 1100 times smaller than that now, so still huge.

There may be a neutrino background behind the CMB, where the universe was even smaller, and the gravitational wave background behind that with even more of a size difference.

[bloopernova]

Would the universe in those other 2 older events have been 2 orders of magnitude smaller still? Have there been any estimates made for the sizes in each "event"?

Are there even more events further back, or is the next one after gravity the big bang?

What a fascinating subject, thank you for expanding my own little universe!

[ben_w]

I'm skim-reading on mobile right now, so here's some more information, but I didn't see anything about how much the universe expanded since 1 second after the big bang, which is the relevant number for the neutrino background:

https://en.wikipedia.org/wiki/Cosmic_neutrino_background

https://en.wikipedia.org/wiki/Neutrino_decoupling

and for gravity:

https://en.wikipedia.org/wiki/Gravitational_wave_background

[bozhark]

Plays right into the white hole theory, interesting

[bloopernova]

As in a white hole is the big bang? That has a kind of poetic symmetry to it, with black holes (big crunches?) being the end, and white holes being the beginning of our particular universe.

But our universe has black holes in it. Forgive the layman thinking, but does that mean we're just one of an infinite series of "nested" universes?

[pelorat]

The energy in our universe is not unlimited, so perhaps each black hole spawns a new universe, and each has less and less energy in it. Think about, WHY is there a certain amount of energy in the universe? Why not more or less. Maybe it's just universes all the way down.