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From: Luigi Fortunati <fortunati.luigi@gmail.com>
Newsgroups: sci.physics.research
Subject: Re: Experiments on the validity of Relativity
Date: 6 Jun 2024 11:31:45 GMT
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Il 05/06/2024 09:10, Jonathan Thornburg [remove -color to reply] ha scritto:
> Luigi Fortunati <fortunati.luigi@gmail.com> wrote:
>> This is what happens to accelerometer 1 in my animation
>> https://www.geogebra.org/classic/vtvnm8uv where you don't notice the
>> contraction and stretching of the springs just because the variations
>> are too small to be visible.
>>
>> But just increase the force of gravity to realize that it doesn't show
>> zero acceleration at all.
>>
>> Look what happens to accelerometer 2 which is also in free fall in a
>> gravitational field: does it seem to show zero acceleration?
> 
> Your animation shows the accelerometers placed in an ambient gravitational
> which varies significantly across the dimensions of the accelerometer.
> We don't expect an accelerometer to work properly in such a situation.
> 
> The definition of an "ideal" accelerometer includes (among other
> conditions) measuring acceleration-relative-to-free-fall at a *point*,
> i.e., it assumes that tidal fields are negligable, i.e., it assumes that
> the accelerometer is small compared to the scale of variation of any
> ambient gravitatonal fields.  Your accelerometer #2 violates this
> assumption.

You judge the tidal forces during free fall to be negligible based only 
on the dimensions of the accelerometer and do not consider the 
gravitational mass: tree falling in the Earth's gravitational field is 
not the same as free falling in that of a neutron star!

They are both free falls but the negligibility is not the same.

Consider an accelerometer made of a single diatomic molecule of hydrogen 
H2, does it seem small enough to make the tidal forces negligible during 
the fall towards the neutron star?

It seems not to me.

The tidal forces on this microscopic-sized accelerometer are so little 
negligible that they manage to break the H2 molecule into two separate 
and distinct H atoms: where is the negligibility in this free fall?

Luigi Fortunati