# [ExI] Chips The Size Of[interplanetary] Dust [and matrioshkabrains]

spike spike66 at comcast.net
Mon Sep 3 03:56:24 UTC 2007

```Russell, this turns into an interesting question of autonomous manufacturing
optimization and launching of nodes, as well as optimization of the use of
energy from sunlight.  Going with smaller and more numerous nodes has an
advantage that is related to an engineering textbook problem from a signals
and systems class I took way too many years ago.

Imagine you have a signal you wish to transmit distance x.  You can do it
with one transmitter and one receiver, but you could put another receiver at
x/2, amplify the signal and retransmit another x/2 to distance x.  This way
you actually have two transmitters, but each one requires only one fourth as
much power as in the first case, so together they only require half as much
power.  Now imagine three receivers and transmitters, each transmitting a
distance x/3.  Each requires one ninth as much power, so together they
require a third as much power as in the first case.  And so on.  Cool, huh?
Perhaps you worked the same problem.

As for station keeping, as the node size scales downward, gravity becomes
less the driver and electrostatic forces ever more important.

My intuition tells me that building an M-brain is optimized by making the
individual nodes as small as our technology permits.

spike

> -----Original Message-----
> From: extropy-chat-bounces at lists.extropy.org [mailto:extropy-chat-
> bounces at lists.extropy.org] On Behalf Of Russell Wallace
> Sent: Sunday, September 02, 2007 5:06 PM
> To: ExI chat list
> Subject: Re: [ExI] Chips The Size Of[interplanetary] Dust [and
> matrioshkabrains]
>
> On 9/2/07, spike <spike66 at comcast.net> wrote:
> > I once spent a lot of mental energy trying to figure out how to do
> > station-keeping with M-brain nodes approximately the size of a dime (but
> > much thinner).
>
> What would you see as the advantage of making them that small? Seems
> to me things are easier and more efficient if you agglomerate a decent
> amount of machinery together in a single mass, for a Dyson sphere
> maybe km-size nodes. We break things up into small units like cell
> phones because we have a particular need to make them that small, but
> when we just want total computing or other throughput we use smaller
> numbers of larger units.
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```