Re: The Big Crunch may be a possibility

On 3/22/2025 1:44 AM, jillery wrote:

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

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

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On 20-Mar-25 17:33, RonO wrote:

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

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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?
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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?

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I'm fairly out of date on this, but before the discovery of dark energy,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.)
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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.
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Fascinating stuff. Thank you for sharing the article!
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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.
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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?
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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.
 

An explanation.
https://www.facebook.com/neildegrassetyson/videos/how-the-universe-expands-at-light-speed-with-neil-degrasse-tyson/523350765610844/
The claim is that the expansion of space accelerated faster than light for parts of the universe that are no longer visible to us.  Space expanded and nothing really accelerated to faster than light, but they are just too far away to observe.  There was the initial inflation when space expanded much faster than the speed of light creating a "flat universe" with just the right amount of mass and energy to keep it from collapsing.  Dark energy is supposed to account for the continued expansion of space within the universe.  One article that I recall claimed that the visible universe extends out to around 45 billion light years in all directions from where we are.  The visible light has to be younger than the age of our universe (less than 14 billion years), but space has expanded.
It doesn't matter, what I wanted was if the mass of the universe estimate includes the mass that is not observable.  We have the background radiation map of the universe, and estimates based on what we can see (these are based on the observable universe).  The estimates would have included what we could not see within the visible universe because we lacked the ability to detect the light from the distant objects.  Did this estimate also include the mass that was too far away to be visible?  How do we know how much mass is no longer visible and is beyond the horizon of what we can see?  We've been trying to estimate the amount of dark matter within the visible universe, so how would we measure the amount of matter further away than the visible horizon? Even though we can't observe it, it is still part of our universe.
Ron Okimoto