[extropy-chat] Clock rate or rather communication delays

[Eugen Leitl]

On Sun, May 07, 2006 at 11:23:00PM -0400, Keith Henson wrote:

> All this indicates to me that  you think computation per joule is going to 
> be a consideration up there with c/second.  Even if you have lots of 
> energy, it's no good if your brain catches on fire.

With current high-flux reactor cores we can easily remove some 20 MW
from a volume of a paper basket. Whether with weaved buckytronic,
cooled by a stiff flux of helium through orthogonal nanotube channel array 
or fractal channels in diamond or sapphire I don't see how you 
could dump enough power into a ~l chunk of machinery while doing
computing and being unable to cool it.

Dark horses like reversible computing and nonclassical computing
even not considered.
 
> >If you look into Nanosystems,
> 
> My wife is listed as one of the editors.  I read it first in draft.

Yeah, I read it as a preprint too, as one of my organics profs
was doing a stint in Stanford before. He thought it was crap, I wasn't
so sure. It took me a while to understand why machine-phase is so
different from both biology and organic chemistry.
 
> If you can keep the average thickness down to the equal of a few nanometer 
> of aluminum you can float on the light and surround the star without being 
> in orbit.  If you leave the cover off one side, the star becomes a 
> fusion/photon drive (for those not in a hurry).

Yes, but I want to power hardware. Whether um or mm, that's way too heavy
to be anywhere else than in orbit. Solid shells could be an option for
small (<100 km) assemblies around a central power source (microsingularity,
or matter/antimatter reactor). I can't quite imagine a cloud of fat nodes, 
each with a tokamak rotating around their own gravity center. It strikes 
me as improbable, though I can't put my finger on it. It's probably the bloat.
 
> If you are going to orbit, a computation node becomes mostly power plant 
> and radiator.  In 1979 Drexler and I wrote a paper for a conference at 

To minimize signalling latency you have to have a spherical assembly.
I'm assuming a large flat panel powering a small spherical (cubical)
computation node, and talking to neighbour nodes in flyby by line of
sight laser.

> Princeton on space radiators that used ground up rock as the heat transfer 
> medium.  I scanned in a copy of it a few days ago if you would like to see 
> it. One of the discoveries we made is that radiators have a inherent square 
> root dis-economy of scale.

What I see as a problem if that the node density is so high you no longer
have an occasional line of sight to colder space to dump heat to. There
might be ways to have the inner cloud work at some 800 K, and reradiate
it a couple of times, until you eventually power some ultra-cold machinery
lighthours/lighdays away from the hot core.
 
> >Because you see where you're going in advance, mapping dust is not difficult.
> 
> I would be really interested in how you would do this.  If you are going to 
> probe the path to the target with a laser before launch, you might as well 
> launch at 1/3 c.

I mean you're looking towards the star you're travelling to, so you use star's
photons to see how much dust is there. Moreover, you're launching with a high-power
microwave beam (by a said circumstellar assembly, acting as a phased-array
microwave source pushing your carbon sail(s), with the trailing probe(s).
The photon flux is dense enough to heat your carbon sail to white incandescence,
so it's going to clear a path in the interstellar medium before you come through.
You could still meet a pebble, but that's what redundant probes are there for. 
 
> 10 exp 13 years might try the patience of even the immortals.

They need not be immortals, nor do they need to be very smart. I don't
expect Darwin to exist the stage to the left. Postbiology is like biology,
only more so.

Some of them will be smart. Some of them will be gods. But even gods have 
fleas. And a metabolism.
 
> That's about what I get.  Spiffy, but the stars recede out of reach.

The local ecology will never interact with antipode ecology, but it
continues nevertheless. A cubic mile of circuitry is also harboring
an ecosystem. 

Does inviduality have to cease to exist? I don't think so. Our cells
have individual indentities, and bees and people have individual identities,
even though being part of a superorganism.

If you tweak a cell, it will jump. If you poke a bee, it will sting.
If you kick a human, he will respond -- though you might send a diplomatic
note or try a hostile takeover if you want to evoke some high-order
behaviour.

So I think even Very Large Beings will be highly responsive on the local
scale. But it could take a megayear to get a meaningful high-level
response. That's okay, though, because whoever that great whale is
singing to is a leviathan just as ponderous and slow.
 
> It could happen.  It could also be very different.

No disagreement. But I have to use specific models in order to deal
with postbiology.
 
-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
______________________________________________________________
ICBM: 48.07100, 11.36820            http://www.ativel.com
8B29F6BE: 099D 78BA 2FD3 B014 B08A  7779 75B0 2443 8B29 F6BE
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 191 bytes
Desc: Digital signature
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20060508/42ca475a/attachment.bin>