Re: Newton's 3rd law is wrong

On 12/2/24 2:10 AM, Luigi Fortunati wrote:

I am not the first to say that Newton's third law is wrong.

Hmmm. Your arguments are all wrong, because you keep omitting important
effects. (You have repetitively posted so many invalid arguments that
many/most participants around here simply ignore your posts.)

Einstein said it before me (implicitly), with his General Relativity.

No, he did not. Your notions about GR are seriously wrong.

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

I never click on such links.

[...]
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. It is possible to only APPROXIMATELY
separate it as you assume, and that approximation destroys your argument.

But the two curvatures are not equal!

Of course not! Granting your separation, their effects are not equal,
either. The effect of earth on moon is huge and causes the moon to orbit
around the earth. The effect of moon on earth is MUCH smaller, and
merely makes it wiggle a little bit as it orbits the sun.

Consider a solar system with just sun, earth, and moon (i.e. ignore
everything else). The earth does not orbit around an ellipse, not even
approximately -- it is the earth-moon barycenter that orbits around the
(approximate) ellipse you are thinking of. The earth wiggles around that
(approximate) ellipse. The wiggles have period ~ 29.5 days,
corresponding to the moon's orbit. (This is exact in Newtonian
mechanics, but only approximate in GR -- NM is linear while GR is not.)

And therefore, even for Einstein, the gravitational equality between
the two opposing bodies no longer exists, ]...]

Hmmm. Newton's third law discusses FORCES, not "gravitational equality".
In Newtonian mechanics, because earth and moon have such different
masses, the effects of equal forces on them are most definitely NOT
equal. In the spacetime curvature interpretation of GR there are no
gravitational forces, and one simply cannot apply any of Newton's laws.
(But one can apply the Newtonian approximation to GR, and all three of
Newton's laws apply within that approximation.)

Hint: it is outrageously arrogant to think 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. There is a reason that no
journal articles have been published on this....

Tom Roberts