Re: starship-design: Re: Why go to the stars? - Kyle

[Steve VanDevender <stevev@efn.org>]

kyle writes:
 > >  > Besides, the speed of light CAN be increased by many
 > >  > factors.
 > > 
 > > Which are not demonstrably relevant to space propulsion.
 > 
 > Untrue. Several ideas (which I won't even quote, since no one will
 > listen) have shown such potential. Oh, Id like to ask: did blowing up
 > the Bikini Atoll with an H-bomb show relavant potential for starship
 > engines? Not at the time. See my point?

I guess you haven't seen the designs for interstellar spacecraft that
actually use hydrogen bombs for thrust.  The British Interplanetary
Society floated one of the proposals.  Just build a big durable plate,
put your payload and a stack of H-bombs on one side, and every so often
toss an H-bomb behind the plate and detonate it.

Your point basically doesn't work because working hydrogen bombs, as a
demonstration that it is possible to artificially induce nuclear
fustion, _did_ show relevant potential for starship engines at that
time.

 > >  > I know everyone will eat me alive for using
 > >  > not-so-exact terminology, but I ask everyone: have you sent a
 > >  > MACROSCOPIC object up to relativistic speed? Here's where I really get
 > >  > demanding: With an engine attached? I believe the answer is no. See my
 > >  > point?
 > > 
 > > Several astrophysical phenomena demonstrate relativistic effects on
 > > macroscopic objects that are completely consistent with the theoretical
 > > predictions.
 > 
 > Oh, I see. I'm unsure of this: Do these phenomena have Engines? ONBOARD?

These phenomena demonstrate that chunks of matter, not just subatomic
particles, can travel at relativistic speeds and behave as predicted by
theory.

The crucial point is that relativistic motion is understood,
experimentally verified, and even observed in natural phenomena.  This
makes it certain that it is possible to build a means to artificially
accelerate objects to relativistic speeds.

On the other hand, FTL is not theoretically supported, experimentally
verified or naturally observed.  This makes it pretty hard to argue that
you can artificially induce FTL motion.  Anyone who believes it is
possible will have to demonstrate it working to be taken seriously in an
engineering context.

The summary of Alcubierre that I've seen (the abstract of his own paper)
is that _if_ you could create "negative energy density", _then_ you
could conceivably induce FTL motion.  However, even he admits that such
negative energy densities have not been created or observed, and that
there is only a somewhat tenuous potential for them allowed by quantum
mechanics.  This is a long way from an engineering design, much farther
than even exotic but physically accepted possibilities like antimatter
propulsion.

 > > If you spout nonsense in this forum, you will be called on it.  That's
 > > all there is to it.
 > 
 > I have already been given permission to post my design. And my theories
 > are NOT nonsense. Perhaps this trouble is due to the fact that I'm just
 > a kid?

I consider your theories too speculative to base a working enginnering
design on.  As far as I'm concerned your age doesn't matter, but the
quality of your ideas does.

 > > 
 > >  > "The suppresion of hard ideas is not the road to knowledge"
 > >  >                      -Carl Sagan
 > > 
 > > You take this quote entirely out of the context and spirit in which it
 > > was offered.  If you have a real FTL theory, then you can justify it by
 > > experiment.  Until you've done so it's not science and it can't be used
 > > to build a working spacecraft.  If you're feeling suppressed because I
 > > keep asking you to put up or shut up on your FTL imaginings, then too
 > > bad.
 > 
 > Have we propelled objects, ARTIFICIAL objects up to .9XXC? No. Therefore
 > that, if what you say is true, is not applicable to starship design. I
 > know my ideas are speculative, but if we cannot speculate, then we are
 > unworthy of being called scientists. No offense to anyone: You shoot
 > down all my theories, but an even more speculative theory, the "cellular
 > automaton universe", you do not attack. Something doesn't add up...

We have a rigorously tested set of physical laws that say it is entirely
possible to accelerate mass to high fractions of c.  These same laws
don't allow mass to travel faster than c.

 > I don't wish to dissapoint you, but you haven't made me feel like an
 > unknowing idiot. Maybe I don't know as much as some in this group, maybe
 > I'm not a colledge grad (yet), with a big degree behind me, but I'm not
 > stupid. I'm beginning to feel a lot like Nicolaus Copernicus. And no, I
 > won't shut up and be a nice little boy. I, unlike some people (I'm not
 > refering to anyone in LIT, so don't get me wrong), am not easy to give
 > up.

If FTL is possible and going to happen, then it won't happen just
because you fervently wish it to be so.  If you really believe it can be
done, then build the device to do it.  If you can even reliably make
subatomic particles travel faster than c for extended periods in free
space, then that will put FTL on a theoretical grounding more on a par
with relativity.

I don't expect you to "shut up and be a nice little boy", but I do think
that any designs we come up with have to be rigorously justifiable.  If
a design requires technology that we don't have, then it needs to show
how to create that technology.  And if a design violates the known laws
of physics, it has to show that those physics really are possible,
hopefully in the same way that other scientific theories are verified:
by experimental proof.