Re: The CMBR falsifies SR


"tomgee" <tyropress@xxxxxxxxx> schrieb
Ilja Schmelzer wrote:
<cmaj10@xxxxxxxxx> schrieb
In GR, Einstein said that we don't know that there truly exists any
inertial frame. But if there were any absolute frame, we would for
sure
know that there are some inertial frames.

Sorry, but this is nonsense. Inertial frames are not defined in GR.

Hold up a minute here. Just because they are not defined in
GR does not mean his point is invalid. All he's saying is that
we cannot find an inertial frame wrt the universe from where
we can measue the motion of a single object.

GR lives without a notion of an "inertial frame" and is doing fine.
To search for an inertial frame you have first to define its meaning.
A system of coordinates where every worldline defined by
x^i = const is geodetic?

In this case, Robertson-Walker-coordinates are an "I-frame".
Nonetheless, such "I-frames" will not be helpful if you consider
something inhomogeneous.

I-frames are
not real wrt the universe, we can only make them up. An I-
frame is simply a point of reference in our minds. They are
not real "frames" in space, they are suppositions from where
observers are said to be observing.

If we define them as special systems of coordinates, they
define solutions of the Einstein equations. These solutions
are global, not associated with any partial observer living
on some single worldline.

An I-frame is one in which we are stationary within it.

An I-frame as defined above does not know about some "we".

A notion of an "I-frame of observer x" is not known in GR
and I see no reasonable way to define it (the definition I
suggested defines only a global property of being an
"I-frame", without dependence of observers.

Without clear definitions of your notions I cannot follow
your argumentation. I do not even understand what you
want to show.

Ilja


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