alternative engines

[steve ravet]

Pat Ford wrote:
> 
> Previously, you (Aaron Willis) wrote:
> > At 02:22 PM 5/5/99 -0700, you wrote:
> > >How about if ya had a HUGE donut shaped container, in space, and spun i
> > >REALLY fast so as to force the air to the outside of the donut, THEN fly
> > >an airplane within that 'SIMULATED' atmosphere?  It would work...
> > >
> > >Now you've heard of an atmoshpere existing without gravity...
> 
> don't all object exert a small gravatational pull ( I think I heard that
> years ago). doc should know?

Yes.

> 
> >
> >       Ha...ALMOST!  Even I caught this one.  I'm going to count that centrifugal
> > force that threw the air to the outside of the donut as gravity in this
> > example.
> >
> 
> I think gravity is a different animal.

Gravity and acceleration are equivalent in relativistic physics.  There
is an "equivalence principle" proposed by Einstein that states that no
experiment can be devised that can distinguish between gravitational
forces produced by mass, and acceleration forces produced by changes in
velocity.  This principle caused him to propose that light is bent by
the sun, and although that particular experiment was flawed, it's been
established since that gravity does in fact cause light to bend.

--steve


-- 
Steve Ravet
steve.ravet at arm.com
Advanced Risc Machines, Inc.
www.arm.com