They could also mean the early, hot universe vs. today. In those hyper-dense conditions, it's possible that something like nucleonic matter could form the compl

They could also mean the early, hot universe vs. today. In those hyper-dense conditions, it's possible that something like nucleonic matter could form the complex patterns of life and intelligence, which would proceed many orders of magnitude faster than our own chemical reaction based life and intelligence. (See Robert Forward's "Starquake" books about life on the surface of a neutron star. Those creatures would experience time at millions of times the speed we do.) Entire eons of civilizations could have arisen and disappeared, with their own "heat death" of the universe from their perspective. At some point, the universe would expand and cool to the point that the form of matter required for their existence would generally cease to exist, destroying everything from their civilization, utterly and completely. In Roger Penrose's Conformal cyclic cosmology, another universe could arise after the heat death of our own, just at a different scale in time and space, where the cold, thin, red-shifted to oblivion photons left over from our universe would comprise a Big Bang in a far slower, cooler, and vaster universe. https://en.wikipedia.org/wiki/Conformal_cyclic_cosmology https://en.wikipedia.org/wiki/Conformal_cyclic_cosmology