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"Einstein's [static 1917] model ... was unstable like a pencil balancing
on its point ... In 1929 Edwin Hubble showed that the universe was
expanding." Einstein missed his big chance to have predicted what Hubble
found since it was there in his theory.
"Inflation ... Alan Guth's 1981 theory ... offered an explanation for
why the initial conditions in the big bang should be approximately but
not exactly uniform ... the fundamental forces ... have different
strengths ... in the very early universe ... the cosmological constant -
the energy density of the vacuum - could also be different in that early
phase." p. 165
This requires the torsion field extension of Einstein's 1915 theory
because there
Guv + /\guv = 0
in vacuum before there is any real matter.
Guv^;v = 0 Bianchi identity
guv^;v = 0 metricity
Therefore
/\^,v = 0
i.e. /\ the cosmological constant is really a constant as well as being
uniform.
When there is real matter we can have
(string tension)/\^,vguv + Tuv^;v(Matter) = 0
So that creation of on-mass-shell real matter will also cause the
cosmological constant to go non-uniform and dynamic, (i.e. to change it
from a constant to a variable) even without torsion. However, torsion
allows the cosmological constant to go non-uniform and dynamic without
creating real matter that is a nuisance for the practical metric
engineering of warp and wormhole. Of course the ET Aliens visiting us
have figured all this out.
Guth assumed that the dark zero point energy density was positive and
enormous at the creation of our local "past light cone" universe in the
multiverse that has an infinity of parallel worlds.
"My Father's House has many mansions." Rabbi Yeshua
De Sitter (also in 1917) "wondered what would happen if a universe had a
cosmological constant and nothing else."
That is very close to our actual universe BTW, which is 96% variable
cosmological field in which 73% is positive zero point energy density
and 23% is negative zero point energy density. Only 4% is real matter
and radiation on mass shell and less than 1/4 of that 4% is star stuff
and us. We have only really known this since 2002 with any real
precision. It took all the Pundits by surprise. The DeSitter spacetime
"looks like the surface of an infinite hourglass ... a closed
three-sphere universe starting out in the infinite past with infinite
size, contracting at nearly the speed of light. The repulsive effect of
the cosmological constant causes this [space] contraction to slow down
and then reverse. The universe reaches a minimum size, then starts to
expand, slowly at first but then faster and faster, eventually
approaching the velocity of light ... particles ... their clocks tick
slower and slower ... the universe expands more and more between ticks
... the [passive test] particles "see" the circumference of the universe
growing exponentially as a function of their own clock time ... Special
relativity just stipulates that two objects cannot [locally in
coincidence] pass each other [in near collision] faster than the speed
of light. Nothing in special relativity prevents the space between two
objects stretching so fast that a light beam could not ever cross the
expanding distance between them. (p. 168) ... The circumference of the
De Sitter space at its waist can be ... 10^-33 cm ... this universe
would look just like a big bang ... Eventually the high [zero point]
density decayed into the normal vacuum ... into hot thermal radiation
... Guth now understood why the big bang would be so uniform. Regions
that have had time to trade light signals should equilibrate to the same
temperature ... as the universe inflates ... these regions pass out of
causal contact with each other [becoming space-like separated out of
each other's local light cones] ... But after the inflationary vacuum
decays the expansion slows and these regions come into contact again ...
As ... Bill Press has noted, they say hello, goodbye, and then hello
again" - like meeting an old girlfriend after many years. Will the old
romantic sizzle return? Tune in to the next episode. :-)
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