[ExI] upon pondering your next million years

[Damien Broderick]

At 09:52 AM 7/12/2008 -0700, Spike wrote:
>
>Robert Bradbury's essay was extremely thought provoking.  Our list may see
>curious new members intrigued by his work.  I fear some techno-innocents
>might find puzzling some of the concepts that we here find familiar
>territory.  An example is that the Matrioshka Brain is mentioned without
>actually being defined, at least not at the first citing.  Normal people
>will be without a clue.  Perhaps they will scramble for their Google page,
>but some will be on an aircraft at the time, as I was.

The book was meant to have an index, which I'd do. Somehow it never 
happened, although there's a bunch of white paper at the end 
presumably meant for one. However--

I sort of assumed (never wise) that people might read from front to 
back. In my intro, I say:

<Robert Bradbury, a polymath equally at home in computer programming, 
advanced genomics, and nanotechnology, ponders a galactic future in 
which entire solar systems--starting with our own--are stripped of 
their planets to build what he has called "Matrioshka brains." Within 
these immense Sun-orbiting swarms might dwell, by Year Million, 
untold trillions of human minds, no longer embodied in bone and 
protein, cavorting in vastly accelerated virtual realities.>

  Steve Harris, in chapter 3, states:

<we'll be building clouds of solar collectors out of the "metals," to 
catch all of the Sun's light, with information processors, powered by 
this energy, at nodes somewhere within the cloud. After the man who 
first envisioned such engineering, such a cloud is called a Dyson 
Swarm. For computation, we need nodes with dense processor 
connection, because otherwise we have speed of light connectivity 
problems. However, we can't put the entire computronium collection in 
one place, because its self-gravity will cause it to collapse, and we 
also have a lot of heat to get rid of, because it won't be perfectly 
efficient. Both of these things will dictate a mix of nodes and 
connections. Robert Bradbury's chapter addresses the tradeoffs of 
problems in making Matrioshka brains or MBrains (planet mass onion 
shells of distributed processing nodes, associated with clouds of 
solar collectors around light sources such as stars and fusion 
reactors). But if you imagine a cloud of collectors and processor 
planetoids, all bound together by coherent beams of connecting 
radiation, you have the idea. Such a cloud would orbit a star or any 
smaller fusion source putting out light.>

Chapter 6, by Wil McCarthy, states:

<Programmer and theorist Robert Bradbury has suggested an interesting 
twist on the Dyson sphere concept, which he discusses further in the 
next chapter: the "Matrioshka Brain", a series of computronium shells 
surrounding a star like nested Russian dolls, each layer powered by 
the waste heat of the layer beneath it. This probably represents the 
most powerful computer that's physically possible to build, although 
it might be capable of other interesting tricks as well. >

So by the time we got to Robert's chapter 7, I assumed that readers 
would be generally prepped for further discussion. Nothing is more 
tedious than a book where each chapter painfully repeats what's 
already been explained.

But I agree that this can create problems for people hopping about in 
the book. My fault for not pressing harder for an Index. But there 
were a lot of last minute problems; astonishing typesetting errors 
whenever superscripts or subscripts appeared, etc. The best-laid 
plans of mice and Matrioshkas...

Damien Broderick