Spacetime

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Sujet : Spacetime
De : hitlong (at) *nospam* yahoo.com (gharnagel)
Groupes : sci.physics.relativity
Date : 25. Jun 2024, 13:20:20
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Organisation : novaBBS
Message-ID : <46633b77bddb3b8bcf79567060ac4687@www.novabbs.com>
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“spacetime is likely to be an approximate description of
something quite different.” – Steven Carlip
It's interesting how most physicists describe spacetime
as an actual "fabric."  It's really a mental model that
may not have any existence at all.  The equations of
relativity describe what actually happens quite well,
but the "fabric" of spacetime may be an invention.
I think the things that are real are THINGS.  I find the
basic concept of string theory very compelling: that is,
elementary particles are not points as the standard model
posits.  In the real world there are no such things as
dimensionless points.  It's a very good assumption because
the string theory particles are way smaller than we can
detect, but presuming elementary particles have extension
in space is surely correct, even though strings may not be.
Some of the things that string theory leads to, however,
are very interesting, such as M-theory and branes.  The
ekpyrotic theory is one that sets forth a reason why the
big bang happened:
https://en.wikipedia.org/wiki/Ekpyrotic_universe
although I disagree with a cyclic universe as presented.
Anyway, that's not necessarily a given in the theory.
The universe may still be cyclic without a contraction
(in agreement with the present information that the
expansion is accelerating).  The energy for a bang comes
from the bashing of an adjacent brane into ours, as
proposed in the original theory and, if it happened once,
why couldn't it happen again?  And again, and again, and
again?
This would shoot down the idea that spacetime (and space)
only extends as far as the last bang (the one nearest and
dearest to our hearts) has had time to expand.
So then the question arises:  what would be the effects
of a previous bang on us?  If we applied GR to that model,
might it not explain some mysteries we are dealing with?

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