Re: MEDIA: NOVA on Gamma Ray Bursters

From: Robert J. Bradbury (
Date: Thu Jan 17 2002 - 13:27:20 MST

On Thu, 17 Jan 2002, Wei Dai wrote:

> Maybe I'm missing some crucial context, but why can't you preprogram the
> agent with the optimal strategies for constructing an M-Brain and a
> transceiver, and then copy yourself over as soon as that's done?

You probably can pre-program something "robotic" with limited adaptive
capability to transform nearby solar systems and then "fork" yourself
into said system (it has to be *very* close however because you need
to build very large arrays of transmitters & receivers to get the
information that one solar system can contain copied over into another
in the brief period that they may be relatively "near" each other).

The problem is, as I believe Ken and Eugene have pointed out, once
copied it doesn't remain the same. I am not the person that I was
10 years ago. Societies of individuals may vary even more.

I don't know how you would go about preserving trust relationships
over 1 million year evolutionary paths much less 100 million year paths.

> Are you assuming that we're only using the star's own energy output,
> without generating additional energy with the extracted material?

So far yes.

> A kg of
> material from the surface of a sun-like star has -2e11 J of gravitational
> potential energy, but it can generate 3e14 J of energy through nuclear
> fusion, so it seems quite feasible to disassemble a star quickly using its
> own material as fusion fuel.

Sure, but you have to have sufficient metals to burn it in a fusion
reactor. Until we have "reasonable" estimates for the metal-to-energy
ratio for a "real" system (say the ITER) it seems difficult to assess
whether star harvesting can be self-bootstrapping. If you've made a
trip through a metal-rich region and built 0.01-0.1 M_sun worth of
fusion reactors, then yes, I agree that would be able to dismantle
stars much faster.


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