Re: starship-design: Something Different...

[TLG.van.der.Linden@tip.nl (Timothy van der Linden)]

Hello Ken,

No strange characters this time? ;)

>I just finished a fascinating book; Time's Arrow and Archimedes' Point, 
>by Huw Price, and Australian Philosopher/Mathematician.

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>So--assuming he's correct--what does this all mean as far as this group 
>is concerned?  First of all, it would seem to rule out FTL virtual 
>particle drives.  The concept of "faster than light" virtual particles, 
>along with non-local quantum effects, stem from our forcing our 
>subjective time-asymmetry onto physics as a whole.

What is a "FTL virtual particle drive"? How is it thought to work?

>Basically, what 
>looks like a faster-than-light occurrence in our temporal frame is 
>actually a combination of a "forward" time causation and a "backward", 
>or advanced causation.  Huw Price shows that any attempt to use a 
>backward causation to set up a paradox will fail; the measurement itself 
>will destroy the correlation you're looking for.  In fact, it looks like 
>you can derive all of modern quantum mechanics from two axioms; 1) 
>Nature is Time-Symmetric, and 2) You can never set up a true paradox.

When talking about FTL (faster than light) I'm always a bit unsure, not
because of the physics involved, but about what the the phenomenon means.
For example does travel trough perminent warped space also count as FTL? 
Anyhow, regardless of how you call it, one day there may exist a possibility
to create permanent "worm-holes" to travel to distant stars in a "no-time".
This phenomenon will likely not depend on tunneling (forward causation) but
instead on general relativity and thus still allows for FTL travel to be
possible.
And regarding tunneling: Since we are "subjective" beings, does it really
matter that we think that we travel faster than light, or that we actually
were at the point of our destination before we really noticed it? (or for
that matter before we even had decided to make the FTL trip)
 
>But the Big Crunch will come with its own Boundary Conditions that will 
>propagate in the reverse time direction from what we're used to.  
>Indeed, on the other side of the universe, Entropy would be increasing 
>in the opposite direction!  You'd get (from our perspective) Inverse 
>Stars that would be coherent radiation sinks, rather than coherent 
>radiation sources.  The laws of electromagnetics account for this 
>possibility in the equations; it just so happens that we never see 
>large, coherent radiation sinks--that's the radiation arrow of time.

What about black-holes? Aren't they coherent enough?
  
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>Anyway, the point is that a large, coherent radiation sink would get rid 
>of a rather painful asymmetry in spaceship engines.  Because there are 
>only coherent radiation sources, we have to Expend mass to gain 
>momentum.  But why not the opposite case; gain momentum by Receiving 
>mass?  A coherent radiation sink would allow this possibility; matter 
>would converge upon it coherently and possibly give momentum to the ship 
>while Adding to the mass of the ship, rather than subtracting from it.  
>A more conventional engine could then operate in tandem, keeping the 
>mass of the ship constant while we gained momentum.

Hmm, how do you get the mass out of the radiation sink (and into the
conventional engine)? Would that not spoil the fun?

Tim