In sci.physics.relativity, PCB

wrote
on Sun, 11 May 2008 07:48:59 -0700 (PDT)
:


PCB wrote:
I read somewhere that only electric currents generate magnetic fields.

Where is the electric current in a permanent magnet?

Is a permanent magnet a frozen electric current in matter?

It seems that the electric current in a magnet would like to flow, but
it cant.

Discus

This is not an obvious relavistic concern;
followups therefore to sci.physics.

Briefly, however, the permanent magnet *is* a manifestation
of an electric current, though it's hard to specify
precisely since I'm not up on my quantum mechanics.
The Bohr model is very discredited by now, but the general
idea is that of a charge orbiting another charge; the
orbiting charge is a current.

Of course in QM things are expressed a little bit
differently, but I've forgotten the details.

Once we've established that an atom has a pair of poles,
it becomes simple, since iron in particular is a series
of magnetic domains, which are crystalline structures
("grains") in the metal; a magnet has more of them lined
up in a preferential direction than not.

--
#191,
Q: "Why is my computer doing that?"
A: "Don't do that and you'll be fine."
** Posted from http://www.teranews.com **