Re: ORIGINAL simple magnets question

["JACK L. URETSKY (C)1998; HEP DIVISION, ARGONNE NATIONAL LAB ARGONNE, IL 60439" <JLU@HEP.ANL.GOV>]

Hi Bill Beatty-
        You write:
*************************************************************
> Well, here I see we meet a serious problem, perhaps the barrier to
> our efforts:
>
>  1. There is no such thing as an *almost* inertial reference frame.
>
>  2. Magnetism is *intrinsically* a relativistic effect. There is
>     never a justification for ignoring relativity when treating
>     questions of this sort. Purcell is a good source for teaching
>     E&M with this fact held constantly in view, as is Feynman.
>     (These two texts were published within a year of one another.)

I agree with both of these.  If we rotate the entire CERN accelerator,
locally each magnet assembly will seem to go in a straight line, but still
there *must* be some GR effects there too.

By number 2, I meant to avoid using electrons which go at 50% of C,
because there *might* be additional effects arising when the disk-magnet
rotates that fast.  Use 1 meter/sec instead, and only deal with the usual
************************************
        1.  There are no GR effects.  See "Electrodynamics on a Merry-Go-Round"
by me and John Ise in AJP about 1958 (sorry, I can't find the exact reference).
There was a subsequent erratum.
See also Misner, Thorne and Wheeler to the same effect.
        2.  As a practical matter, it is possible to show that one cannot spin
real matter fast enough to get relativistic effects.  Stuff comes apart.  This
is an interesting exercise in orders of magnitude.
        3.  The method of analysis for a straight wire should also apply to
a spinning current loop of large diameter.  But you must actually do the calculation!
                                Regards,
                                                Jack

        "I scored the next great triumph for science myself,
to wit, how the milk gets into the cow.  Both of us
had marveled over that mystery a long time.  We had
followed the cows around for years - that is, in the
daytime - but had never caught them drinking fluid of
that color."
                Mark Twain, Extract from Eve's
                Autobiography