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

[Eliezer S. Yudkowsky]

Keith Henson wrote:
> 
> Reactionless drives *are* perpetual motion machines.  If you can't 
> visualize why I can explain the obvious.

Actually, I can't see this as obvious.  Suppose the reactionless drive 
requires a thermal differential to drive it, and equalizes the thermal 
differential in the process.  How would it necessarily violate the 
second law of thermodynamics in the course of violating 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?

The thought had occurred to me, but as a matter of fact, I didn't know 
off the top of my head.  Also, my statement was just with respect to the 
prospect of producing thrust.  Laying waste to the countryside doesn't 
violate *physical* law.

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