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

[Eliezer S. Yudkowsky]

> 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.

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. 
  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.

-- 
Eliezer S. Yudkowsky                          http://singinst.org/
Research Fellow, Singularity Institute for Artificial Intelligence