From: Randall Randall (randall@randallsquared.com)
Date: Sun Jun 08 2003 - 22:22:12 MDT
On Sunday, June 8, 2003, at 11:25 PM, Hal Finney wrote:
>
> As the star passes by an observer, the field points to the current
> position of the star. That's because the field is moving uniformly
> with
> the star. In the case of a wooden framework, the beams would point
> directly at where the star is right now, because that is how the frame
> is
> built.
>
> It turns out that gravity is not unique in this respect. Electric
> fields
> work the same way. If the star carried an electric charge, and you had
> an instrument to detect it, the instrument would be attracted towards
> the current position of the star, not to where the star was in the
> past.
> It's for the same reason, that the electric field moves along with
> the star.
If this were true, wouldn't it follow that one could build an FTL
communications device consisting of a sufficiently precise detector
and a movable highly charged object? For this reason alone, it seems
implausible that electric fields behave as perfectly rigid objects, as
you describe.
No doubt there's some bit I haven't caught. :)
-- Randall Randall <randall@randallsquared.com> "Not only can money buy happiness, it isn't even particularly expensive any more." -- Spike Jones
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