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Old August 24th 05 posted to sci.physics,sci.physics.relativity
Ben Rudiak-Gould
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Posts: 1,116
Default Galaxies expanding with space? The Space Stretch

Spoonfed wrote:
The diagrams you have drawn show a Galilean Transformation, showing a
fairly small change in speed, less than ten percent of the speed of
light. This would cover the area within a billion light years of
Earth; within 10% of the radius of the universe.


First, that's the radius of the *visible* universe; nobody knows how big the
whole universe is. Second, in terms of comoving distance the radius of the
visible universe is about 47 billion light years, so one billion light years
is a lot less than 10%.

When we get outside that range, if Hubble's Law still holds true, we
need to use a Lorentz Transformation, as the Galilean transformation is
only an approximation.


As I've said before, the Galilean transformation is a better approximation
than the Lorentz transformation in this situation. More precisely, fix an
object O which is roughly stationary with respect to the CMBR, and choose
coordinates such that time is cosmological time and distance from the origin
is comoving distance from O. The coordinate systems so obtained, for
different objects O, are related by a coordinate transformation which is
similar to the Galilean transformation.

I know we've talked about this before, and I recall you said that you were
aware that your ideas were different from mainstream cosmology. If so, I
think you should tag your posts with "this is just my personal theory,
but...". And you should be aware that your model, if I understand it
correctly, is a special case of the standard big bang model with Omega ~ 0,
but Omega has been known to be about 1 for a long time. For as long as I can
remember, the only debate has been over whether it is slightly larger or
slightly smaller than one. Zero is way outside the error bars.

-- Ben
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