Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: Is an electron a perpetuum mobile?

Learn more physics!

Most recent answer: 02/17/2013
Q:
As far as I know electrons have a spin, meaning they are rotating. So since electrons have mass, are spinning electrons form of perperuum mobile
- Milan (age 19)
Serbia
A:
Electron spin certainly isn't the type of perpetual motion machine that people seek. You can't get any work out of it. Since there is no such thing as an electron without its spin, it doesn't mean anything to even say what the energy of the spin is. It's all part of the rest-mass energy of the electron. So it isn't really any more of a perpetuum mobile than any old particle just sitting around.

That said, we can still ask whether the rest energies of particles will themselves "run down", i.e. convert to thermal energy with higher entropy. It appears that the answer is yes. It seems that things gradually fall into black holes, then radiate out as Hawking thermal radiation. So even plain old rest mass runs down.

Mike W.

(published on 02/17/2013)

Follow-up on this answer.