From: Robert J. Bradbury (bradbury@ilr.genebee.msu.su)
Date: Sun Jan 16 2000 - 11:04:10 MST
Damien,
This is a linear run-through of what you sent to me.
Lord only knows on the original order, but I assume
you know where this stuff is ending up.
=========================================================================
Re: Damon Knight's "A for Anything" & assembler monopolies.
The problem with this is that the technologies you need to construct
assemblers are going to become increasingly commonplace. If trends
in the miniaturization of disk drives continue, I expect in a few
years people could disassemble a couple of disk drives and have much
of the hardware required for precise 2-D positioning. You can generate
buckytube AFM tips in an electric arc device with carbon electrodes.
Any hobbyist can now purchase peizoelectric positioners, lasers for
measuring tip position, etc. In short it will be extremely hard to
control access to the materials you need to produce AFMs, from there
the path to assemblers is only a matter of creativity and time.
An entirely alternate path would use protein synthesizers available
in most university molecuar biology departments. Do your design
on a computer, synthesize the proteins, let them self-assemble and
voila...
So I'm very doubtful that limited access to these technologies will
be a reality, unless a substantial majority of people supports this
for safety reasons. (I.e. designs must be verified as safe before
assembly.) This is kind of like "speed limits". Everyone hates
them, but generally agrees they are required and conforms "more
or less" to the rules.
Re: Neal Stephanson's "drab uniformity" of public-access nanomaterials.
This seems doubtful as well, since one would suspect pressure for
publicly supported competitions or simple artistic expression to
produce creative designs. Unless the human "ego" disappears with
the nanoera, there will always be people who derive satisfaction
from observing people driving "their" cars, wearing "their" clothes,
living in "their" houses, etc. The fact is that in a "free support for
the masses" era, creative people will have that much more time
and opportunity to design things that eliminate the uniformity.
Re: My analysis of assembly of food, houses, swimming pools, etc.
> Start by buying an acre of cheap land somewhere with at least modest
> sunshine. Your nano compiler will grow you solar cells that cover most
of
> the land, providing 400,000 watts a day, powering the compilation of
around
> 10 kilos of materials per hour.
After some discussion of this with Robert Freitas, it seems I may have
been a bit generous with the available power levels on the surface of
the Earth. It may be something like 1370W/m^2 in the upper atmosphere
but at the surface, in the visible region most effective for power
harvesting, it may only be ~400W/m^2. To be on the conservative,
you might want to adjust this by saying something like "several (2-8?)
acres of land, depending on your latitude and cloud cover", that
probably provides a sufficent "fudge factor".
> Sounds mad. Actually, friendly critics swiftly pointed out that
> Bradbury's 1999 estimates might be too cautious by a factor of 100.
My limits are "ecological", not "physical" (perhaps, worth point out
a little more clearly than is mentioned, since it implies to the
"greens"
that we *are* thinking ecologically!). My limits were sharply
constrained
by heat limits that dictate the total mass & energy of nano-constructors
per
person (Nanomedicine, Volume I, pg 175) Robert's power limits are less
than
mine (~100W/person), so you would have to have a family of 3-4 people to
"allowably" use 400KW/day. Now (obviously), you can store waste heat
and
radiate it at night, construct cooling towers into the stratosphere
or "save" (in a virtual-bank) nano-constructor operating time (you can
have it now, but you have to pay it back in the future (with interest)
or use some fraction of it to increase the global cooling capacity).
> Bradbury, recall, opted for 400 KW. But with all that excess carbon
being
> drained from the atmosphere, putting the Greenhouse effect
conveniently into
> reverse, we might need all the heat we can get.
Very nice touch!!! Perhaps ... "Bradbury, whose father served on
his home town's conservation commission, conservatively opted for
400 KW... :-)
Re: Fermi Paradox
> Perhaps the nearest to such a explicit perspective is the `dirt'
theory
> suggested ebulliently, perhaps tongue-in-cheek, by Stephen Witham.
`Any
> sufficiently advanced communication,' he proposes, with a nod to
Arthur C.
> Clarke, `is indistinguishable from noise.
A good point, also made by Minsky at one of the early SETI conferences.
{ Communication with Extraterrestrial Intelligence (CETI), Proceedings
of a conference held at the Byurakan Astrophysical Observatory, Yerevan,
USSR, Sept. 5-11, 1971 (Ed: Carl Sagan, MIT Press, Cambridge, MA (1973)
}
Heaven help us if the Aliens decide to use spread spectrum frequency
shifting to lower their power requirements.
> Anyway, computer design is well understood, and data routing and
> bit-exchanges don't look one whit like noisy dirt. Get out of here!
Whomever said this should leave their computer modem speaker "on"
when they connect at anything above 4800-9600 bps. It sounds like
static. They don't understand anything about Shannon's theories.
> This universe of Lem's, torn asunder in conflict over its very
> architecture by titanic Exes and Powers, is saved from utter ruin by
the
> laws of game-theory, which ensure that the former combatants must
> henceforth remain in strict isolation from each other.
I'm not sure that you can conclude this from game theory. Game
theory states that both parties can come out ahead *if* you trust
each other. Now, if Robert Freitas is correct, and advanced
civilizations evolve to maximize the sentience quotient of the
universe, then "discovering ways to trust" becomes a major goal.
So, remaining in strict isolation, *might* promote longevity,
but it may not promote maximization of knowledge or wisdom.
It begs the question of whether it is better to simply survive --
knowing you are less than you could be -- or whether living life
in the fast lane, rising to the peaks of success, only to leave a
pretty corpse (if you bargained poorly with the devil) is a better way
to go. Fundamentally -- do civilizations choose to "shoot the rapids"?
> Something professional cosmologists fail to acknowledge (I can see
their
> faces screwing up already) is that the observable universe might
indeed be
> at least somewhat engineered.
I've seen their faces -- its the sign of the cross that believers
present to ward off vampires!
> True, the earliest stars would have been deficient in heavy elements,
> but there have been stars like the Sun for many hundreds of millions
> if not billions of years longer than our own 5 billion year-old star.
Kardashev has spoken to this in several papers. Since the heavy element
producing stars go supernova within a few hundred million years and the
current estimates for the age of the universe are ~15+ billion years",
it is *highly* likely that the basic requirements for "life like ours"
have existed for a period between 5 and 10 billion years before our
solar system even came into existence. We are 2nd or 3rd generation
galactic inhabitants. Only if the probabilities for the evolution
of intelligent life are very very rare indeed has there been no
previous Spike.
Re: M-Brains and seeing them
> That's the intriguing question. Obviously the entire radiation
budget of
> a blazing star has to be re-transmitted by the outermost shell--but it
is
> spread across a radiating surface at least as wide as the orbit of the
> Earth, and recovered from the bottom of the thermodynamic cascade. So
the
> star will look dim, exceedingly dim. Maybe so very dim that even if
> nine-tenths of the cosmos is already transformed in M-Brains, all
you'll
> easily detect will be the influence of their stars' gravity. They will
> be... dark matter.
Actually, a very "young" M-Brain, might have a shell of earth-orbit size
(constructed in a few dozens of years). Older M-Brains (after large
planet dismantlement) would have shells of Neptune or Pluto (or even
greater)
orbit size. The fundamental constraints are (a) how much power is the
sun
producing; and (b) what is the size of the shell needed to radiate that
power at slightly above the background temperature; and (c) is there
enough
material in the solar system to radiate that power at that temperature?
For our solar system, without stellar mining, we can probably build
shells out to Neptune, but after that things get a little bit
questionable.
The fascinating thing is that M-brains "evolve" as they accumulate more
radiator material from their "giant" planets and eventually their star
(using star-lifting). The older they are the colder they are and less
visible they are.
Re: D.B. question on a previous post
> [one question - why did you say `diamondoid biochemistry system'
rather
> than `diamondoid chemistry system'? Slip of the typer? Or do you think
> carbon will be positionally assembled by enzymes or some such?]
Probably because I'm thinking more in terms of a "biochemistry"
mind-set. It might be interesting to think in terms of an "ecological
system" (I think Forrest Bishop thinks more this way). If you
get locked into "bio" meaning "life", then this narrows your point
of view, and it takes some exploration of what life really is --
"Life is a negentropic and self-organizing aperiodic crystal"
(Xenology, Chapter 6) to open the mindset a bit.
Since ideally in a very efficient system, we would not only build
diamondoid/saphire/tungsten-carbide components but recycle the
"undamanged" (by radiation) components as efficiently as possible,
I tend to think of this as "biochemistry", since one of the hallmarks
of biology is that for the most common reactions it tries to be as
conservative with energy utilization as possible.
Probably more accurately it would be "nano-ecology systems".
> [R.B.] draw a useful distinction between three distinct
> orders of nano minting: self-replication and self-assembly (both of
which
> life already does, and which biosynthesis methods will emulate) and
precise
> molecular assembly, which will allow us to build mansions and
spaceships
> out of diamond.
Actually, current bacteria & eukaryotic cells *do* do all three
(self-replication, self-assembly and molecular assembly). You
may want to draw the distinction between soft/wet molecular assembly
(biology) and hard/dry assembly (diamondoid/saphiroid/etc.) for which
we currently have no "live" prototypes and only hypothesis of how
we might construct the new "nano-ecologies". My main point is that
hardest part ("hard" molecular assembly), need not be solved to have
most of the advantages of "nanotech".
> ...Bradbury observes, is limited by the strength of materials
> like bone, hydroxyapatite (teeth), sea-shells and bamboo--somewhat
lower
> than steel and concrete. But semi-intelligent pieces of steel or
concrete
> could self-assemble, or bamboo-beamed houses could `grow' themselves.
This is documented in Nanomedicine, Volume I, pg 295. There is only
a moderately small difference between the strength (Young's Modulus)
of wood (~1x10^10 N/m^2), bone (~2-3x10^10), Nautilus shells
(4.4x10^10),
enamel (7.5x10^10), steel (1.9x10^11) and diamond (1x10^12). The less
than ~two orders of magnitude strength difference translates to roughly
a 1 order of magnitude difference in areal dimensions. As a first
order
approximation a 2"x6" wood support would tranlsate to a ~1 in^2
diamondoid
support. (Please note this is not exact, I need formulas that are back
in Seattle to do this conversion completely accurately.)
For wood, bone, shells and enamel, we already have the nanoassemblers.
For steel we need "intelligent" MEMS driven self-assembly. Only for
the final step of diamondoid molecularly assembled, self-assembled,
self-replicating machines do we need a significant amount of "new"
invention.
> Interestingly, methods for achieving these small interim breakthroughs
were
> worked out several decades ago, before nano-engineering had been
suggested.
Damien, if you are refering, to von Neuman's self-replicating machines
or the NASA study on self-replication, this statement should be
footnoted
or referenced (it took me a while to understand what you might mean).
If you are refering to the subsequent discussion of Santa Machines
(ala Theodore Taylor), then it is ok, though back references to
von Neumann and the NASA study would be useful.
Thats it for this batch. I think there is one more commentary
re: "final summing up" to go.
Robert
[P.S. Damien, pls confirm your receipt of this to me personally.]
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