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Old February 5th 19, 02:59 AM posted to sci.astro
Eric Flesch
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Default General Cosmology: universal expansion as an illusion of changing spatial curvature

On Mon, 4 Feb 2019, (Steve Willner) wrote:
(Eric Flesch) writes:
The current Standard model is underpinned by the "flat universe",
a spatial manifold of zero curvature with local perturbations.


Why do you think that?


I've never yet seen calculations done onto evolving spatial curvature.
Nowadays only static flat is used, particularly since the measurements
(including that impressive Planck paper which you referenced) show a
flat universe. But if we see a flat universe, there can really only
be two possibilities: (1) it is flat, or (2) it isn't flat but looks
like it is. (2) is the generalization of (1).

(1) The value of lightspeed (c) varies with spatial curvature.
Hyperbolic space would look to us as the same as "flat", but if you
travel in it you will find that your destination is closer


Which distance did you have in mind?


For example, at z=1, c would be twice the value. This is as seen
natively, that is a local observer at z=1 sees a flat universe just
like ours but with c twice as fast. But that universe (at z=1) has
twice the spatial curvature (on some absolute scale) as ours, so c is
still invariant by some curvature-compensated measure.

All of them change with spatial curvature, but changing speed of light
would be new physics.


I'm trying to *get rid of* new physics, specifically dark matter, dark
energy, and inflation, just by using spatial curvature. We know c to
be invariant, but that assumes no dependence of c on spatial curvature
-- as seen locally. I haven't found any work done on that topic --
would be interesting if there were some.

The possibility that lightspeed is decreasing with universal time...


Isn't this ruled out by observations?


No because we've observed only here in this local place. If
physicists looked for a migrating value -- a very tiny change over
decades -- maybe they could find it. Consider the standard kilogram.
It seems the oldest physical ones are annoyingly heavier by some
infinitesimal amount. They blame contaminants for that -- mercury
contamination in particular, but I think they're just guessing? If c
is migrating to slower -- some imperceptible amount except to
oscilloscopes -- physical things would be measured to grow
correspondingly -- especially if you tie the meter to c, as is done
now. That they have done so, makes it that much harder to measure a
change in c, like tools have been disabled. Does it actually make it
harder to *even just think about*?!? Maybe it wasn't such a great
idea to define a unit of length in terms of c.

Changing speed of light changes the ratio of frequency to wavelength.
That would mean grating spectrographs, which measure wavelength, would
get different results than radio observations, which measure frequency.
In other words, redshifts would differ between radio and optical
measurements.


No, the frequency is invariant but the wavelengths compress with the
slowing light -- so it looks the same as if both here & there were
flat. My model may be wrong but not for that reason.

Eric