Re: starship-design: starship design: Alcubierre Drive... How?

["Kyle R. Mcallister" <stk@sunherald.infi.net>]

AJ Crowl wrote:
> 
> Hi Group,
> 
> Alcubierre's original design was flawed by the size of the warp-bubble which
> requires immense amounts of energy to create. Such bubbles have an energy E
> ~ R^2 / Lp , where Lp is the planck length [1.6 x 10^-35 m !], so for any
> velocity V the total energy for his design was ~ -6.2 x 10^62 kg * v, which
> is about 10^10 times the mass of the visible Universe for even just
> lightspeed. So how to avoid such a HUGE energy bill? 

Correct. But consider this: if it is found that spacetime can be bent by
means other than concentration of mass, I.E., you can produce some kind
of 'field' that interacts with space more strongly than matter, your
problems could be solved. How can this be done? Good question...

> Make the geometry different and fit your flat space [R ~ 200m] into a tiny warp bubble 
> {tiny ~2000 Lp}which is possible. Doctor Who's TARDIS couldn't do better. For the
> same energy [milligrams] as the bubble slows down it gets larger, until you
> can get out again, but the bubble walls become thinner than Lp very quickly,
> so it's unclear whether it can be done. Planck's length is the limit of
> space fuzz, as far as we know. Chris Van Den Broeck, the designer, is a bit
> unclear and he's not too sure what process would produce enough negative
> energy to make an Alcubierre warp, but he hopes that his proof of principle
> study will inspire more brains to work on it.

Negative energy might not be the key, see above. There are some
scientists, notable Terence W. Barrett and H. David Froning, who have
taken a 'step back', so to speak. They note, and I agree with them, that
there are too many speculated points in all these theories about faster
than light travel. Simply writing up a paper that says 'this is how you
travel FTL' is no good, in my mind. First, we must try to answer some
basic questions, such as: what is spacetime? What are its properties?
How can we interact with it? What is the nature of the speed of light?
Granted, we have theories such as relativity, that help us to picture
what happens, but we still do not know much about it. Light is a very
curious form of energy. It is not clear what the factors are that limit
it to 300,000 km/sec. Once we understand these factors, we may be closer
to knowing what it takes to travel faster than light. Who knows? It
might turn out to be simpler than what we currently think. But I don't
think we will be able to do it for at least a few hundred years.

Kyle R. Mcallister