[extropy-chat] Relativity drive: the end of wings and wheels?

[Keith Henson]

At 10:46 AM 9/8/2006 -0700, Eliezer wrote:
> > The best I've found so far is here:
> > http://www.shelleys.demon.co.uk/fdec02em.htm
>
>On the one hand, it claims that this operates within the laws of
>physics; that is, a conventional calculation will show that this is a
>reactionless drive.
>
>On the other hand, they provide no numbers or calculations and while
>IANAP I'm pretty damned sure that the laws of physics prohibit this.  To
>be specific, it appears to violate conservation of momentum.  As I
>understand it, conservation of momentum is a fundamental consequence of
>   the laws of physics being invariant under translation in space.  Since
>every elementary event known to physical law obeys conservation of
>momentum, all larger systems also obey conservation of momentum.
>
>If they told me that microwaves shot out the other end, I'd be far more
>willing to believe it.

I wouldn't.  You have any idea of what a microwave generator with 2 gms of 
thrust would do to the countryside?

>As it is, my reading is that if this were true it would be front-page
>news in every newspaper on the face of the Earth and would necessarily
>involve DRASTIC changes to the fundamental laws of physics.
>
>IANAP but this sounds completely unbelievable.  But then it is not the
>place of transhumanists to substitute themselves for the physicist
>community in judging claims of perpetual motion or reactionless driving.

Reactionless drives *are* perpetual motion machines.  If you can't 
visualize why I can explain the obvious.

>   When it hits the cover of _Science_, then report on it.  (New
>Scientist is not a trustworthy source.)
>
>Of course it is also possible that e.g. microwaves do shoot out the
>other end, and the nontechnical press has simply failed to grasp this.

See above.

Keith