From Newsgroup: sci.physics.research

On 12/16/24 4:24 AM, Luigi Fortunati wrote:

Tom Roberts il 12/12/2024 09:20:30 ha scritto:

With my animation https://www.geogebra.org/m/v33hu4en I show what
Newton said.

I never click on such links.

My Geogebra works are the heart of my proofs and thought experiments.
And you make your judgments without even looking at them.

But your statements here show a major lack of understanding, and invalid attempts to intermix Newtonian mechanics and General Relativity.

[...]
Instead, Einstein argues that there is no force between the particles
of the Earth and those of the Moon, and that the action between the two
bodies is due to the space-time curvature of one in contrast to the
different space-time curvature of the other.

That is not correct. Using the spacetime curvature interpretation of GR,
it is the curvature due to ALL components of the solar system that
determines all of their orbits.

What do the curvatures due to all the other components of the solar
system have to do with it?
And while you're at it, why don't you add all the other galaxies in the universe?

Yes, in principle one should do that. In practice their effects are
completely negligible.

The Earth's effect on the Moon is *much* larger than the Moon's effect
on the Earth because Earth's spacetime (which is more curved than the
Moon's) acts on the Moon *more* than the Moon's reacts on the Earth.

Hmmm. To claim that you must assume separation. But as I have said
several times before, GR is not separable like that. Removing the earth
from consideration affects the moon's path enormously; removing the moon affects the earth's path by only a small amount.

[...]
Hmmm. Newton's third law discusses FORCES, not "gravitational equality".

No, Newton's third law talks about "action and reaction" and not just
forces.

But TO NEWTON, "action and reaction" here refer to forces, not some
nebulous and undefined notion of yours. Your arguments here are based on
PUNs. (Nomenclature has changed over 300 years, and translation from
Latin adds additional ambiguity and potential for confusion.)

[...]
The third law can (and should) be applied in General Relativity because
it does not speak of forces but of action and reaction.

Strictly speaking, GR does not use forces to model gravitational
interactions -- it uses geometry [#]. But see above for the PUNs you use
here, which destroy your claims.

[#] in the geometrical interpretation of GR, which we are using.

The spacetime of General Relativity (with its curvature) acts between
the Earth and the Moon as the tension in Newton's string acts between
the horse and the stone.

That is not how GR actually models this. Geometry (spacetime) does not
"act", it just is. Moreover, GR is not separable, as you implicitly
assume here.

GR uses very different concepts from Newtonian mechanics. But you keep attempting to use Newtonian concepts to "describe" GR -- that's invalid.

[...]
I don't think I can see a mistake, I *prove* that the mistake is there
(for those who watch my animations).
An error that neither you nor anyone else have been able to detect.

Because there is no error, except by you.

I repeat: it is outrageously arrogant to think that you alone can see an
error in a theory that has stood the test of time for hundreds of years
and inspection by tens of thousands of physicists. As I have said
before, you REALLY need to take a course in physics at a college or university....

Tom Roberts
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