Editing Openai/6921ae73-3700-8000-8ab7-90012976bb8a (section)

==== If density slowly increased instead of decreased: ====
# No hot, dense early phase → broken Big Bang story In our universe: - Early high density + high temperature explains: - The cosmic microwave background (CMB) - How light elements (hydrogen, helium, a bit of lithium) formed If the universe started low density and only later got dense: - You don’t get the right early “nuclear furnace” conditions. - You wouldn’t get the same helium/hydrogen ratios we see now. - You wouldn’t get the CMB the way we observe it.
# Gravity behavior would be weird As density grows: - Gravity gets stronger overall. - The universe might start to recollapse, forming black holes and super-dense regions earlier. - Structure formation (galaxies, clusters) would happen differently or violently.
# Life probably doesn’t show up If the universe is: - Initially too empty → no stars form for a long time. - Later too dense → things get crushed, heated, or destroyed as gravity ramps up. You’d either get: - A long “boring” phase with nothing much, - Then a violent crunch phase where everything collapses. Not great for stable, calm environments where life can chill for billions of years.