From: Alejandro Dubrovsky (s328940@student.uq.edu.au)
Date: Thu Jul 03 2003 - 10:05:57 MDT
On Fri, 2003-07-04 at 01:14, Spike wrote:
> --- Spike <spike66@comcast.net> wrote:
> >
> > Subject: Solar sailing vs. laws of physics ?
> >
> >> The reflected photon would have the same
> >> frequency as the pre-reflection photon
> >> only if the light source and the reflector
> >> are stationary with respect to each other.
but, spike, the dude doesn't claim that solar sails break the first law
of thermodynamics (energy conservation). he claims the second (getting
work done at 100% efficiency) would be broken. I don't know enough
physics to tell wether he's right or not, but his basic argument seems
to be:
solar sail starts propulsing => solar sail gets hot => solar sail stops
working. I understand why the first step happens but not why the second
step is necessarily so (unless it gets hot enough for the beast to break
up, which it would if it would reach the temperature of the photons
hitting it)
alejandro
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