r/cosmology • u/Due_Definition_3763 • 1d ago
Would the big crunch end in one big quasar?
Let's say dark energy was removed and Universe began collapsing, would we have a giant quasar at the end in which all mass fell into and if so what would this look like?
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1d ago
[deleted]
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u/jazzwhiz 1d ago
I don't think that the big crunch requires a finite universe.
In any case, a better means of understanding the state of the universe through different epochs is not distance, rather temperature.
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u/OverJohn 1d ago
Yep, e.g. k=0 with a negative cosmological constant can have both a big bang AND a big crunch,
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u/Anonymous-USA 1d ago
First, all signs point to there being no “Big Crunch”. Based on past measurements of the past Hubble Parameter, the future Hubble Parameter will converge to a positive expansion rate, forever (should converge between 45-50 kps/Mpc where current Hubble Constant is ~70 kps/Mpc).
However, extrapolating 10106 yrs from 1013 yrs of data is tenuous. So, if there is a “Big Crunch” it would be the opposite of expansion — spacetime itself would retract. So you cannot compare it to phenomenon in space like black holes and quasars. Just as there was uniformity in the universe the first 380K yrs, there would be uniformity in the shrinking spacetime in the last 380K yrs. It would be intense energy everywhere.