[ExI] Von Neumann Probes

[John Clark]

On Fri, Jan 23, 2026 at 5:44 PM Ben Zaiboc via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

*> Even if there are many many technological civilisations in our galaxy,
> it would be like a handful of fireflies in a continent-spanning
> rainforest. *


*Not if one of those many technological civilizations had developed Drexler
style Nanotechnology, then they'd be about as obvious as a supernova.   *


> * > I appreciate the 'von Neumann probe' argument, but not all
> civilisations are going to go that route*


*It would only take one. And I'm not talking about one civilization, I'm
talking about one individual in a civilization. It is simply not **tenable to
maintain that precisely 100% of the technologically savvy individuals in
the observable universe have decided not to make a Von Neumann Probe. I
think William of Ockham would agree with me that the best explanation of
the Fermi Paradox is simply we are the first. And as I keep saying,
somebody has to be. *

*> I have a hunch that we tend to vastly underestimate the difficulty of
> interstellar travel.*


*You don't need interstellar travel to make a Dyson sphere/swarm, and
something like that should be very noticeable, but we have noticed nothing.
And any technological civilization worth its salt should be able to get a
Von Neumann Probe moving at 1% the speed of light because its mass would be
very small, and so it could get from one side of the galaxy to the other in
just 10 million years, a blink of the eye cosmically speaking. But just how
much would a Von Neumann Probe weigh? *


*Estimates vary, Freeman Dyson thought it would be about a kilogram but
George Church and Zaza Osmanov think that's much too high, they think with
advanced Nanotechnology one Von Neumann Probe could be about the size of a
bacteria and, depending on various engineering considerations, weigh
between a trillionth of a gram (10^-12) and a thousandth (10^-3) of a gram;
and, if it had access to raw materials and light energy from a star, it
could make a copy of itself in about a year. Then after 79 years there
would be an Avogadro's number of Von Neumann Probes, 6.02*10^23. And one
year after that it would be obvious to a blind man in a fog bank that not
all the technologically knowledgeable minds in the galaxy were on the
Earth. But we have seen nothing like that. I think I know why. *

*John K Clark*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20260124/79d4ec1f/attachment.htm>