Re: Bioastronomy [was Bloated Stars and excess IR] (fwd)

Robert J. Bradbury (
Fri, 13 Aug 1999 13:16:38 -0700 (PDT)

> John Quinley <> wrote:

> You know, I've never really thought about those big planets being brains of
> some sorts. This is really not my expertize, but a reason that these
> civilizations might have went with this design is that, due to the light
> cone, it was the best mechanism to maintain conscious coherence. Perhaps
> there are some cooling issues here, to. Spin the brain so that only part of
> it is actually soaking up sunlight and storing it, while the other part is
> pointed into space. Just some thoughts.

There structure of a sphere, where every "node" on the sphere has a line-of-sight direct communication path to every other node on the sphere is a logical implementation for optimal communications when you are using photons as your carrier wave. The two problems that I had with it were: (a) I couldn't figure out a configuration for > 10^19 transmitters

      and receivers at *each* node.  Since I think we are material
      constrained anyway, having that many transmitters & receivers
      at each node seemed to only make things worse.  This is particularly
      true when the materials required are things like Galium, Arsenic and
      Indium that aren't very abundant.  I punted and went with a hexagonal
      configuration where each node only communicates with its nearest
      neighbor.  All nodes act as routers to other nodes in the net so
      all messages get delivered sooner or later.
  (b) It wasn't clear to me what happens when you have photons from
      10^19 to 10^38 beams crossing each other at the center of a sphere.
      I'm pretty sure that you have problems due to EMF interactions
      but I'm not sure at what density level the photons really start
      to interfere with each other.  At some energy density, I presume
      we turn energy into matter, yes?  The receivers aren't going to work
      for long if they are designed to receive photons and protons arrive
      instead.  [Comments from the hard core physicists are welcome.]

You presumably could fill the sphere with fiber and prevent interactions between the beams but you are likely to run into a materials shortage again.

If it turns out that you want to optimize communications over either computation or memory, I would agree that J-Brains/Zeus structures may be the way to do this and that they are likely to be small due to materials limitations.

As you point out, there are likely to be cooling problems. You could spin a sphere, or you could simply "flow" the heat through the structure.

It is worth remembering, that the astronomers are *presuming* these objects are planets (because that is the only meme their minds currently hold). They could be Borg cubes, collections of planetoids, etc. All we know about them with current data are the minimum mass estimates, orbital periods and eccentricities.