[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