# Inertia and Relativity

Discussion in 'Alternative Theories' started by hansda, Dec 22, 2017.

1. ### hansdaValued Senior Member

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Particle electron has intrinsic magnetic moment, which is due to its intrinsic spin. That means its intrinsic spin is physical. So your above statement is quite wrong.

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3. ### hansdaValued Senior Member

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deleted due duplication.

Last edited: Mar 17, 2018

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5. ### NotEinsteinValued Senior Member

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8. ### NotEinsteinValued Senior Member

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Spins are physical, yes. But it's not due to rotating particles. As the article states: "we have come to realize that it is misleading to conjure up an image of the electron as a small spinning object."

So my statement was correct, and your calculation in post #98 is wrong.

9. ### hansdaValued Senior Member

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"..."At our current level of understanding, the elementary particles are quarks, leptons (such as the electron) and bosons (such as the photon). These particles are all imagined as pointlike, so you might wonder how they can have spins. A simple answer might be, perhaps they are composite, too. But deep theoretical reasons having to do with the rotational symmetry of nature lead to the existence of spins for elementary objects and to their quantization. ..."

10. ### NotEinsteinValued Senior Member

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Yes, and that's fully compatible with what I've been saying.

And the article also mentions this, which I already brought up before, which you ignored back then: "Based on the known sizes of subatomic particles, however, the surfaces of charged particles would have to be moving faster than the speed of light in order to produce the measured magnetic moments."

11. ### hansdaValued Senior Member

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You can also read this following quote from your link "... "Spin is the total angular momentum, or intrinsic angular momentum, of a body. The spins of elementary particles are analogous to the spins of macroscopic bodies. In fact, the spin of a planet is the sum of the spins and the orbital angular momenta of all its elementary particles. So are the spins of other composite objects such as atoms, atomic nuclei and protons (which are made of quarks). ... "

12. ### NotEinsteinValued Senior Member

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Yes, and I fully agree with that. Note how that doesn't say that:
- spin is not physical;
- intrinsic angular momentum must mean rotation;
- quantum spin is the rotating of particles;
- quantum spin is identical to the spinning of composite bodies (notice the word "analogous");
- non-composite particles or point-like particles are physically rotating.

13. ### hansdaValued Senior Member

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As per my math $c=k_1rw$. Here tangential speed can be $v_t=rw$. Here $v_t$ can be considered as $v_t<c$.

14. ### NotEinsteinValued Senior Member

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Sure, you can consider that, but does it work out? Please demonstrate that when you put in the numbers for (for example) the electron, this holds.

15. ### hansdaValued Senior Member

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Electron has a compton wavelength which is non-zero. I think earlier I explained, how compton wavelength can be related with its actual radius. It is four times the compton wavelength reduced over 2 pi. So $r_e=4\frac{\lambda_c}{2\pi}$.

Last edited: Mar 17, 2018
16. ### NotEinsteinValued Senior Member

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That is not an answer to my question. Please don't quote my post if you are not responding to it at all.

17. ### hansdaValued Senior Member

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See this link https://www.sciencedirect.com/science/article/pii/S0370269316300776 . This shows a non-zero radius for quark. But your link considers quark as a point particle. So your link is not very correct.

18. ### NotEinsteinValued Senior Member

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Wrong; it gives an upper limit. We've been over this: setting an upper limit doesn't mean it's non-zero.

And because you've misread that article, this conclusion is unfounded.

Edit: Oh, and once again you're quoting my post without responding to it. Please stop doing that!

19. ### hansdaValued Senior Member

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Well, non-zero upper limit does not suggest a zero radius that it should be called a point-like. I am just showing that your link is not very correct. So electron tangential speed need not be superluminal to produce a finite magnetic moment.

20. ### NotEinsteinValued Senior Member

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Calling it a "point" is indeed wrong, but calling it "point-like", as in "currently indistinguishable from a point" isn't really. It's at best sloppy. But, as usual, scientists know what is meant by the term, and it's just used as a convenient short-hand, so there's no problem there.

Which you have failed to do so far.

Which you have failed to demonstrate at all.

21. ### hansdaValued Senior Member

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There is no math in your link to prove superluminal speed for finite magnetic moment. I dont know on what basis this statement was made.

22. ### NotEinsteinValued Senior Member

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In case you have forgotten, we talked about incompatibilities between a non-zero electron radius, the idea of a rotating as a basis for its quantum spin, and the theory of relativity; a point you couldn't even coherently respond to (post #66).

Here's another link, which might help you understand the posed problem: https://www.researchgate.net/post/W...ming_the_classical_spin_model_of_the_electron

Yes, that's because you ignored the issue around post #66.

And once again, you quote my whole post, without responding to (most of) it. Can you please stop doing that?

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