Faster than light electron spin

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Discussion Overview

The discussion revolves around the concept of electron spin and its implications regarding speed, particularly in relation to the speed of light. Participants explore theoretical calculations related to angular momentum and the radii associated with electron spin, while also referencing classical and Compton radii.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant notes that while electrons are not literally spinning, they are curious about the speed required for the observed angular momentum, suggesting extreme values like 100 times the speed of light.
  • Another participant mentions the theoretical radius of the electron being zero, while referencing the classical electron radius and discussing how moment of inertia and velocity relate to radius.
  • Some participants encourage calculations using the reduced Compton wavelength for the radius, indicating a playful approach to the problem.
  • There is a hypothesis that the electron's charge radius might be similar to that of the proton, with speculation about the relationship between their magnetic moments and spin speeds.
  • One participant expresses skepticism about the radii of electrons and protons being the same due to their mass differences, while suggesting that spin velocities might be identical.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the calculations and assumptions about electron and proton radii, as well as the implications for spin velocities. The discussion remains unresolved with no consensus reached.

Contextual Notes

Limitations include the dependence on definitions of radius and the theoretical nature of the calculations proposed, as well as unresolved mathematical steps regarding angular momentum and spin velocity.

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I understand that we are not to think of an electron literally spinning on its axis because the equatorial speed would far exceed the speed of light. However, just for fun, I've been trying to find out just what the speed would be to make the numbers come out to agree with the observed angluar momentum. I've seen 100x the speed of light and 10^32 radians/s. But at what polar radius is that? Anyone have more info on this?
 
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The theoretical radius of the electron is 0. But people often use the classical electron radius http://en.wikipedia.org/wiki/Classical_electron_radius
Note that as you get smaller, the problem gets worse because the moment of inertia goes as R^2, and velocity at the edge of a rotating body goes as R.
 
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Your question is "just for fun", so go ahead and do the calculation and do not worry about light speed. Use the reduced Compton wavelength for the radius. What do you get?
 
liometopum said:
Your question is "just for fun", so go ahead and do the calculation and do not worry about light speed. Use the reduced Compton wavelength for the radius. What do you get?

Just for fun I predict electron 'charge radius' is the same as that of proton, and since proton has smaller magnetic moment I bet it's spinning with less speed than electron.
 
My focus is on the Compton radius (Compton wavelength divided by 2 pi). The radii of electrons and protons will not be the same due to the difference in masses.

I suspect you will find that the spin velocities are identical.
 
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