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> http://www.amazon.com/Relativity-Its-Roots-Banesh-Hoffmann/dp/0486406768
> "Relativity and Its Roots" by Banesh Hoffmann, Chapter 5.
> (I do not have the text in English so I am giving it in French)
> Banesh Hoffmann, "La relativite, histoire d'une grande idee", Pour la
> Science, Paris, 1999, p. 126:
> "Dans un cas, je compare votre horloge a deux des miennes; dans
> l'autre, vous comparez la mienne a deux des votres; ceci permet a
> chacun de nous d'observer, sans absurdite, que l'horloge de l'autre
> est plus lente que la sienne."
>
> Translation from French: "In one case, I compare your clock with two
> of mine; in the other case, you compare my clock with two of yours:
> this allows each of us to observe, without absurdity, that the clock
> of the other is slower than his own."
>
> The following observer has two clocks placed on the periphery of a
> rotating disc, and is going to compare them with a single non-rotating
> clock (at rest):
>
> http://www.bartleby.com/173/23.html
> Albert Einstein (1879-1955).  Relativity: The Special and General
> Theory.  1920.
> XXIII.  Behaviour of Clocks and Measuring Rods on a Rotating Body of
> Reference
> "An observer who is sitting eccentrically on the disc K' is sensible
> of a force which acts outwards in a radial direction..."
>
> The only difficulty comes from the fact that the two rotating clocks
> are not inertial. However, by increasing the diameter of the disc
> while keeping the linear speed of the periphery constant, one can make
> them virtually inertial.
> That is, Einsteinians will make two simple modifications in Einstein's
> rotating-disc experiment:
>
> 1. The non-rotating clock (at rest in K) is no longer placed at the
> center of the disc; rather, it is outside the disc but close to the
> rotating periphery where it can be directly compared with passing
> rotating clocks fixed on the periphery.
>
> 2. Einsteinians will increase the diameter of the disc while keeping
> the linear speed of the periphery constant. So clocks fixed on the
> rotating periphery will become virtually inertial.
>
> The two modifications will allow Einsteinians to prove, in accordance
> with Einstein's 1905 light postulate, both:
>
> 1. that rotating clocks run slower than non-rotating clocks.
>
> 2. that non-rotating clocks run slower than rotating clocks.
>
> Finally, Einsteinians will see in the dictionary what REDUCTIO AD
> ABSURDUM means.

Silly walkers at the Perimeter Institute

http://www.youtube.com/watch?v=IqhlQfXUk7w

inform Einstein zombie world about non-reciprocal time dilation
related to the rotating disc. Only the final result is given: the
assumption is that Einstein zombie world knows how to deduce it:

http://www.perimeterinstitute.ca/Outreach/Explore_Our_Universe/Essence_of_General_Relativity/
"So let's imagine that Alice and Bob have identical watches as before,
with Bob floating freely "at rest" outside the space station (he is in
a spacesuit doing a spacewalk), watching Alice revolving round and
round inside the spinning space station. As Alice comes around, she
puts her watch up against the window and at the instant she passes by
Bob, he sets his watch to read the same time as hers. She then
continues around once (just like walking around the block) and the
next time they meet Bob looks at Alice's watch through the window and
notices that less time has elapsed for her than for him. Time is
moving more slowly for Alice than it is for Bob, although, as
emphasized earlier, she herself does not experience anything out of
the ordinary. It's only when they compare watches that they both
notice something strange is happening."

Pentcho Valev
pvalev@yahoo.com