Re: poly: Solar system development

From: carl feynman <>
Date: Wed Dec 17 1997 - 11:16:14 PST

At 04:28 PM 12/13/97 -0800, Ralph Merkle wrote:
>Some comments on the colonization of the universe:
> [speed = c - epsilon]
>how small can epsilon be? Is it really limited only by the energy
>available to accelerate the seeds?

As the speed increases, new problems crop up, which require new solutions.
i don't even think we've found all the problems, much less worked out
solutions. I recently had a very interesting discussion with Forrest
Bishop, about a scheme he had to launch long thin projectiles to large
fractions of c with a very long electromagnetic accelerator. One problem
that I thought of was that of a damage avalanche: if the probe hits a (more
or less stationary) gas atom while it's whizzing through the accelerator,
this will knock a lot of atoms off the probe. These atoms will be moving
very fast relative to the accelerator, so when they hit the walls of the
accelerator, they will knock off even more atoms, which will hit the probe,
etc. This problem comes up at speeds above a few hundred kilometers per
second. It can be avoided by decreasing the length of the probe or
increasing the spacing between the probe and the walls of the accelerator.
However, the point is that I only thought of this problem in 1996, while
people have been talking about launching interstellar projectiles with mass
drivers for decades. Who knows what hideous problems we haven't thought of

Received on Wed Dec 17 19:08:32 1997

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