Re: The Elevator in Free Fall

On 12/29/24 2:34 PM, Luigi Fortunati wrote:

[...]  *real* gravitational force

You are basing your entire argument on the meaning of one word. That is
NOT physics; at best it is linguistics.

So, it is the presence or absence of *real* gravitational forces in
the "local" frame of the elevator that establishes which of the two
models is correct and which is not.

Complete nonsense.

First, you give no method to determine whether a given force is "real"
or not. You seem to assume that this distinction is obvious, but it most
definitely is NOT, and depends on the meaning one gives to that word.
The validity of physical models doe NOT depend on the meanings of words
-- the models themselves are mathematical, not linguistic. IOW: the word
"real" does not appear in any physical theory.

Second, the ONLY way to determine whether a given model (theory) is
valid is to perform experiments and make measurements on them, then
compare to the predictions of the model for the same measurements of the
same experiments.

Bottom line: if you perform experiments near the surface of the earth,
with measurement accuracies of microns and microseconds over distances
<~ 100 meters and durations <~ 100 seconds, you'll find that both
Newtonian gravity and General relativity are valid. But for certain
astronomical measurements (such as the advance of mercury's perihelion
with arc-second/century accuracy) only GR is valid.

A contestation that I expected and that no one has made is this: if
General Relativity is wrong, why are its results more consistent
with observed phenomena than those of Newton's gravitation?

This is more nonsense. See above. GR is valid over a LARGER DOMAIN than
Newtonian gravity. As I keep saying, "right and wrong" (also "true and
false") are not applicable to physical theories; theories are valid over
a given domain with a given measurement accuracy, and in this case those
domains are different for NG and GR.

I repeat: you REALLY need to learn what physics actually is -- you have
wildly incorrect notions about it. Until you do, you will keep confusing
and mystifying yourself.

[This is getting overly repetitive and boring. Don't expect
me to continue.]

Tom Roberts