[extropy-chat] Singularity heat waste

[Keith Henson]

At 09:34 AM 7/14/2006 -0400, you wrote:
>This comment was recently posted by "Chris" on my blog (responses welcome):
>
>         "Does anyone know if any work has been done on the subject of how 
> much
>waste heat would be generated by a singularity event? I'm thinking in
>terms of the fact that all computation, like all physical action,
>generates at least some degree of waste heat ( just no getting around
>thermodynamics) Assuming our civilization gives rise to a computational
>matrix that independently evolves in processing power exponentially,
>wouldn't that result in a catastrophic and possibly terminal heat-shock
>to the host-biosphere? Maybe that's the fate of all civilizations that
>reach singularities. I'd love it if anyone has any ideas to share on
>this..."

Ultimately, you can't get more waste heat than the energy available.

If you captured the entire output of the sun, and radiated the waste heat 
by a shell somewhat further out than the distance of earth, the temperature 
would not be a great deal different than earth is now (accounting for 
geometry factors).

As likely would be a huge fall in the use of energy by a civilization 
undergoing a singularity.  Consider the inefficiencies of food, transport 
and brain activity.

I posted on this subject to another list yesterday.  Here is an extract.

Date: 13 Jul 2006 08:59:33 -0800
From: Keith Henson <hkhenson at rogers.com>
Subject: Re: "Overpopulation"

 > >There is nothing wrong with a human population of a trillion, that's on 
the
 > >order of 200 times the current population. It is not impossible either,
 > >they could live at 1/10 the current density on earth given just the
 > >material in the asteroids converted to O'Neill colonies.

(snip objection)

It's not an upper bound, just making a point that its the ratio of
resources (including land) to human population that's the problem. Current
population 6+ billion, which for this purpose is close enough to 5. Times
200 that's a trillion. From memory, the asteroids have material to
construct 2000 times the land area of earth if converted to O'Neill
colonies. If you increase the population by 200x and the land area they
have by 2000x, the population density goes down by a factor of ten.

snip comment

I think earth is way over populated right now.

But if you are concerned about heat, the energy budget I remember from the
space colonies studies was about 25kW per person, a big chunk being in
light for food production. The radiator budget per person to dump the
waste heat at near room temperature is 1/4 kW / square meter, or 50 square
meters (both sides radiate). That's 50x10^12 square meters or .05x10*9
km^2 of radiator. Area of the earth is 0.5 x 10^9 so the radiator for that
many people is roughly 1/10th the area of the earth.

It happens that large, fluid dominated space radiators are mass inefficient
on a square root law, i.e., a radiator 100 times as large will have ten
times the mass per kW of radiation capacity. (See the paper Drexler and I
wrote back in 1979.)

This does not put a hard limit on habitat size, but it does make
continental sized ones a lot more massive. If they averaged out at 10^7
each, it would take 10^5 of them to hold a trillion people.

Mind you, while this is physically possible, I don't think it is very
likely any more. :-(  I suspect that people will upload instead of going
out. Think of how many people would live entirely in Second Life if they
could. An almost depopulated world is the background for the Singularty
story I have been writing.

 > >But today's population can't be sustained with the current level of
 > >technology. Something, either massive die offs or a massive technological
 > >shift, seem unavoidable within the lives of most reading this post.
 > >
 > >Since we are the kind of people who consider and bring about 
technology, it
 > >is a subject that should be of interest here.

snip questions

Nanotechnology. Singularity. Google and read Vernor Vinge's paper.

Keith Henson