Re: Spooky Action At a Distance Question

From: Peter Shor (peterwshor_at_aol.com)
Date: 07/09/04 

Date: 9 Jul 2004 04:49:32 -0400

"Nicolaas Vroom" <nicolaas.vroom@pandora.be> wrote in message news:<DdhFc.172371$iL3.8637564@phobos.telenet-ops.be>...
> "David Park" <djmp@earthlink.net> schreef in bericht
> news:oYXBc.9823$bs4.1308@newsread3.news.atl.earthlink.net...
> > I'm also a novice also trying to learn these things.
> >
> > On the question of rigidity in special relativity Taylor and Wheeler have
> a
> > wonderful exercise (L-12, p 116, paradox of the skateboard and the grid)
> in
> > their Spacetime Physics text. A meter stick slides across a floor with a
> one
> > meter diameter hole. If the meter stick is moving at a high speed it will
> > appear shortened in the frame of the hole and fall through. But from the
> > perspective of the meter stick, it is the hole that is shortened and so
> one
> > might expect it not to fall through. But it does because 'rigidity' is not
> > an invariant concept. The meter stick 'droops' and slips right through the
> > hole.
>
> Is this the outcome of a real experiment ?
> If No than this whole discussion has no "value" i.e.
> does not make sense
> If Yes what has rigidity to do with this experiment because
> why considering the meter stick (rod) rigid
> when in reality a rod is not rigid ?

This is a thought experiment, and the object of this thought
experiment should be to convince you that special relativity
predicts there's no such thing as a rigid meter stick.

> If the meter stick drops through the hole as the result of an experiment
> (In reality there should be a small bar at the middle of the hole, other
> wise
> a rod which is almost twice as large as the hole with a small speed
> moving left to right over the hole will drop through the hole)
> then there are two points of view,
> one from the frame of hole (and fall through)
> and one from meter stick (and not fall through).
> If the meter stick drops through the hole as the result of an experiment
> than the second point of view is just wrong.
> and not "because 'rigidity' is not an invariant concept"

> Nicolaas Vroom
> http://users.pandora.be/nicvroom/

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