Re: opposite of relativistic time contraction

Tim Little wrote:
> On 2008-03-15, Ben Crowell <crowell07@[EMAIL PROTECTED]
>
wrote:
>> The WP article on Tipler cylinders was helpful. I was actually hoping
>> to find a method for time un-contraction that *wouldn't* also be a
>> technology for closed timelike curves.
> 
> Just rule in your story that CTCs are impossible due to vacuum
> instability.  It may well be true in the real world, so it's not much
> of a stretch.

Good point, thanks!

>> On the same topic of what you can do if you have access to exotic
>> matter, one possible solution to accelerating a black hole might be
>> to give it a magnetic monopole charge, and then accelerate it using
>> magnetic fields.
> 
> So then how do you accelerate whatever it is producing these fields?
> You seem to have a potential problem of "turtles all the way down".
> If you're accelerating a 10^17 kg black hole at 100 g, you need to
> apply 10^20 N of force to something else in the opposite direction.
> The minimum power requirements also rapidly get icky.

I'm assuming they have godlike resources, so the absurdly large power
requirements aren't necessarily an issue. The point is that it's not
necessarily all that hard, in theory, to accelerate a piece of metal
at 100g, but it's hard to accelerate the tender flesh of a living
creature at 100g without squa****ng it to death. AFAIK, the only way
to accelerate flesh at 100g without causing death is to use
gravitational fields.

> You could in theory fire The Mother Of All Lasers into the black hole.
> 10^29 W or so ought to give 100g acceleration.  Aiming may be a bit of
> an engineering difficulty, but I think we're well past the realm of
> engineering limitations.

Hmm...10^29 W is 300 suns, and you'd have to collimate it into a beam
with a diameter of 0.1 nm. Seems like diffraction would be a problem.

A beam of material particles would have a better ratio of force to
power, but then it has its own problems. If it's got a speed of 10^7
m/s, then it needs to carry 10^13 kg/s, which is enough to double
the mass of the black hole in something like an hour. You'd also form
an accretion disk, which would probably emit enough x-rays to kill
any living thing nearby.

For the requirements of my story, I'm thinking that the magnetic-
monopole-charged-black hole probably works best. All you need is an
absurdly large heat engine to drive an uncrewed rocket ****p, which
then accelerates the black hole with magnetic fields, which then
tows the passenger module using gravitational fields.