The speed of light, John Barrow, and WorldNutDaily
Jason Spaceman
WorldNutDaily site earlier this evening. It can be read here:
http://www.worldnetdaily.com/bluesky_btl/19991011_xcbtl_the_scient.shtml
Basically he goes on about the 'education establishment', Kansas,
evolution, and how ". . .a growing number of scientists are adopting
the 'young Earth' theory. . ." (although he never names any).
Anyways, Farah mentions John Barrow, a professor of math at the U. of
Cambridge. Farah claims that Barrow has shown that the speed of light
has been decreasing. I am curious as to whether Barrow really said
this, or if Farah is misunderstanding Barrow's research in order to
support his young earth beliefs? Can anyone help?
J. Spaceman
Ulf Torkelsson
Well Farah is distorting the truth. One or two years ago Barrow and
a co-worker of his suggested that if the speed of light had been
higher at the big bang than it is now, then that would solve the problem
of causally disconnected regions in the universe.
To be more specific the problem is, assuming that the universe is
15 billion years old, then from all directions we can receive light that
has travelled for 15 billion years, that is the light originated at places
that are 15 billion light years distant. That means that if you first look
to the right and then to the left you see two places in the universe
that are 30 billion light years apart. That is these two places have
not been able to exchange any signals yet, as no form of signal can
travel faster than the speed of light. Still we can measure their
temperature, and we find that it is the same. So how have they
managed to agree on which temperature they should assume?
The easiest cop out would be to say that they had the same
temperature from the beginning, but most cosmologists find that
unsatisfactory. The most popular explanation is the so-called
inflationary cosmology.
Barrow attempted another explanation. If the speed of light was
much higher initially, then places that look like they are casually
separated today would have been able to exchange signals at
an early stage in the evolution of the universe. However a
high speed of light would have messed up the physics of the
universe later, so the speed of light must have dropped to its
current value fast, that is within much less than a second.
So the truth is that Barrow suggested, though he could not
demonstrate that it has happened, that the speed of light
has been decreasing. However the speed of light dropped
to its current value so fast that it does not support any
claims by creationists that the speed of light has been
varying.
Ulf Torkelsson
dkomo
>
> To be more specific the problem is, assuming that the universe is
> 15 billion years old, then from all directions we can receive light that
> has travelled for 15 billion years, that is the light originated at places
> that are 15 billion light years distant. That means that if you first look
>
> to the right and then to the left you see two places in the universe
> that are 30 billion light years apart. That is these two places have
> not been able to exchange any signals yet, as no form of signal can
> travel faster than the speed of light.
Excuse me, this makes no sense. If the universe is only 15 billion
years old, then how can these two places be 30 billion light years
apart? The expansion of the universe could only have lasted 15
billion years, and the expansion rate, assuming it occurred after the
inflationary period was over, was less than the speed of light.
I mean, assume these two points were close together at t=0. At time
t=15 billion years, these two points could not possibly be further
apart than 15 billion light years because of expansion. The only way
they could now be 30 billion light years apart is if they *started* 15
billion light years apart at t=0. But I don't believe that the
universe was this large after the inflation era.
Galen A. Tripp
I would think that if only one were moving, you would be correct.
However, *both* are moving away from us. One off to the left for
fifteen billion years, the other off to the right for that same fifteen
billion years. Each is thirty billion light years from the other. We
are, conveniently, are in the middle. I wonder if there is anything
thirty light years from us.
內躬偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,
Galen A. Tripp Galen A. Tripp Galen A. Tripp Galen A. Tripp
�虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌
-- Galen A. Tripp
President for Life
International Organization Of People Named Galen A. Tripp
(If your name is Galen A. Tripp, ask about our dues!)
<http://www.morbius-tripp.com/>
>
> --dk...@cris.com
Galen A. Tripp
And this is how it would have appeared if I had proof-read a little
better:
"I would think that if only one were moving, you would be correct.
However, *both* are moving away from us. One off to the left for
fifteen billion years, the other off to the right for that same fifteen
billion years. Each is thirty billion light years from the other. We
are, conveniently, in the middle. I wonder if there is anything thirty
billion light years from us.
Nathan Urban
> If the universe is only 15 billion
> years old, then how can these two places be 30 billion light years
> apart?
http://www.astro.ucla.edu/~wright/cosmology_faq.html#DN
Ulf Torkelsson
> "Galen A. Tripp" wrote:
> >
> > dkomo wrote:
> > >
> > > Ulf Torkelsson wrote:
> > > >
> > > > To be more specific the problem is, assuming that the universe is
> > > > 15 billion years old, then from all directions we can receive light that
> > > > has travelled for 15 billion years, that is the light originated at places
> > > > that are 15 billion light years distant. That means that if you first look
> > > >
> > > Excuse me, this makes no sense. If the universe is only 15 billion
> > > years old, then how can these two places be 30 billion light years
> > > apart? The expansion of the universe could only have lasted 15
> > > billion years, and the expansion rate, assuming it occurred after the
> > > inflationary period was over, was less than the speed of light.
> > >
> > > I mean, assume these two points were close together at t=0. At time
> > > t=15 billion years, these two points could not possibly be further
> > > apart than 15 billion light years because of expansion. The only way
> > > they could now be 30 billion light years apart is if they *started* 15
> > > billion light years apart at t=0. But I don't believe that the
> > > universe was this large after the inflation era.
Actually it was much larger after the inflation era.
>
> >
> And this is how it would have appeared if I had proof-read a little
> better:
>
> "I would think that if only one were moving, you would be correct.
> However, *both* are moving away from us.
You should keep in mind that what I had in mind here was photons.
The galaxies in the universe are not really moving.
> One off to the left for
> fifteen billion years, the other off to the right for that same fifteen
> billion years. Each is thirty billion light years from the other. We
> are, conveniently, in the middle. I wonder if there is anything thirty
> billion light years from us.
Most likely there is, but the photons from that region have not
had time to reach us yet. The big bang is not an ordinary explosion,
it is an expansion of space itself, meaning that the distances
between lumps of matter get magnified with time even if the
lumps of matter do not move. The universe may therefore be
much larger than the observable universe, and could even be
infinitely large.
Ulf Torkelsson
Bill McHale
: dkomo wrote:
:>
:>
:> Excuse me, this makes no sense. If the universe is only 15 billion
:> years old, then how can these two places be 30 billion light years
:> apart? The expansion of the universe could only have lasted 15
:> billion years, and the expansion rate, assuming it occurred after the
:> inflationary period was over, was less than the speed of light.
:>
:> I mean, assume these two points were close together at t=0. At time
:> t=15 billion years, these two points could not possibly be further
:> apart than 15 billion light years because of expansion. The only way
:> they could now be 30 billion light years apart is if they *started* 15
:> billion light years apart at t=0. But I don't believe that the
:> universe was this large after the inflation era.
: I would think that if only one were moving, you would be correct.
: However, *both* are moving away from us. One off to the left for
: fifteen billion years, the other off to the right for that same fifteen
: billion years. Each is thirty billion light years from the other. We
: are, conveniently, are in the middle. I wonder if there is anything
: thirty light years from us.
Actually I think we should be careful here in our terminology. The
Galaxies at the edge of the Universe are not really moving away from us in
the sense that we normally think of it. Rather the space between us and
them is expanding, possibly at an increasing rate, therefore normal rules
the speed of light don't really apply. Further if current cosmological
theories are correct, they perceive themselves to be in the middle of an
equally large observable Universe and as a result we are at the edge of
their perception and they have other galaxies equally distant from them in
the opposite direction. Finally of course it is possible that one of
these other galaxies might conceivably be a galaxy we can see at the other
end of our observable Universe depending on how large the Universe
actually is.
--
Bill
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