Re: The Big Crunch may be a possibility

On Fri, 21 Mar 2025 09:30:04 -0500, RonO <rokimoto557@gmail.com>
wrote:

On 3/20/2025 5:27 PM, Kestrel Clayton wrote:

 
 
On 20-Mar-25 17:33, RonO wrote:

https://www.nbcnews.com/science/science-news/dark-energy-changing-
understanding-rcna197386
>
Dark energy may be waning, and the acceleration of our galaxies may
one day end.

 
That's interesting. I couldn't tell from the Berkeley Lab public release
whether this new data suggest the rate of expansion is dropping, or if
the acceleration of the rate of expansion is decreasing (instead of
increasing, which is the current consensus). In other words, is it
slowing down, or just not speeding up quite as fast?
 

What would happen after the big crunch?  Would all the matter in the
universe eventually fall into one large black hole?  How much matter
can a black hole contain before something like the Big Bang happens? 
There is already "evaporation" from black holes.  Would anything send
the evaporation out of control?  Could anything like a Big Bang occur
within a black hole to create a new universe within the event horizon?

 
I'm fairly out of date on this, but before the discovery of dark energy,
the consensus was that the universe is either flat, or so close to
spherical as to be indistinguishable. That would indicate the expansion
of the universe would eventually halt, but the universe would not really
collapse. Instead, given enough time, the stars would all burn out, all
protons would eventually decay, and even the black holes would
evaporate, until all that remains are photons, electrons, and some
other, weirder particles. (However, I know photon decay is currently
considered less certain a prospect than in the 1990s, so YMMV.)
 
Everything collapsing into a massive black hole still seems unlikely,
but if it did, that would simply be a different route to the photon age.
Eventually energy states are so low that quantum phenomena become the
biggest movers and shakers in the universe, and after that... we really
don't know. It's simply off the map, as far as modern physics goes.
 
Fascinating stuff. Thank you for sharing the article!
 

>
Google thinks that there might be enough dark matter and regular matter
in the universe so that the collapse would happen if the expansion stops.
>
One science article that I read recently noted that inflation predicted
that there are parts of the universe that would not be visible to the
Webb telescope.  The fringe of our universe expanded away so fast that
there would be a sort of event horizon past which light has not reached
us inside the visible universe.  Sounds weird, but is all matter further
away than that horizon, part of the calculations about whether the
universe will collapse or not?
>
Ron Okimoto

You confuse inflation, the bang of the Big Bang, with cosmic expansion
apparently due to dark energy.  These are two separate phenomena with
different causes.

Also, it's a matter of observation that galaxies are moving away from
Earth at speeds proportional to their distance.  This necessarily
means that at some distance called the Hubble Sphere, galaxies recede
from Earth faster than the speed of light.  This does NOT mean the
galaxies are moving FTL relative to their local space.

--
To know less than we don't know is the nature of most knowledge