[extropy-chat] Nuclear terraforming

[Robert Bradbury]

Terraforming Chapter 7 has about 70 pages on the "The Terraforming of
Venus".  It has a few pages on the use of nuclear explosions to deflect
asteroids.  This is being studied more extensively in Europe right now as
they are taking a long term interest in the possible need to deflect NEOs
which might intersect with Earth.  Thoughts in this area in the U.S. seem to
involve using a "net" to snare the asteroid/meteorite and dragging it to
alter its course.  The problem revolves around how tightly packed individual
asteroids/meteorites are.  Most (large) inner solar system bodies condensed
out of molten material which tends to facilitate chemical reactions that
bonds small molecules together forming "solid" rock or sufficient
gravitational compression that one gets similar effects (e.g. granite,
marble, sandstone, etc.).  It isn't clear that many/most small bodies in the
solar system (asteroids & meteorites) would have the same cohesiveness (and
so nuclear explosions would result in fragmentation rather than deflection).

However, you are thinking so "old school".  Terraforming was written in '94,
only 2 years after Nanosystems was published and there is little or no
application of nanotechnology to the concept of terraforming (Zubrin largely
makes the same mistake in TCFM though he comes closer when he discusses
using material from Mars to produce large SPS).  I do not believe that
sulfuric acid would create any significant impact on either diamondoid or
sapphire nanorobots.  If you have read any of the MBrain work you have to
question the wisdom of returning *any* material back into the bottom of a
gravity well.  Use the uranium in the nuclear weapons to build nuclear
reactors that provide the power to produce Gadolinium-148 to power nuclear
nanorobots which could simply sort out the H2SO4 molecules from the
atmosphere.  One strategy might be to put down the minimal mass of nuclear
nanorobots that can start constructing bases for buckycable based space
elevators (converting atmospheric CO2 -> nanotube cables + O2).  As you
process the CO2 one can presumably sort out the H2SO4 molecules and convert
them into H2O + S + O2.  Sulfur is largely only a trace element in most
nanomachinery so you probably end up with piles of the stuff.  Once you have
the atmosphere "clear" you can more easily beam SPS based power down to the
surface to power the mining nanorobots to strip the planet of any mineral
bound carbon (CaCO3 =limestone) so you can hoist it back into space.
Silicon probably gets stripped as well for solar cells in the SPS solar cell
arrays [1].  One is probably left with a planet consisting of mostly iron
and an O2 atmosphere.  If there is any amount of water left around this
probably results in the conversion of the surface into hematite (rust).  It
is worth noting that robbing the planet of carbon probably makes it useless
from the perspective of plants (at least those based on currently known
biochemistry).

The entire discussion (that I've seen thus far) assumes that one wants to
terraform a planet in the first place.  Seems questionable to me -- lets go
create more habitats at the bottom of gravity wells making rather poor use
of the easily available resources rather than engineer lifeforms that don't
require gravity and/or make optimal use of the resources at our disposal.

Robert

P.S. I've got *two* copies of Terraforming... :-)  Someday I'll probably put
it online but it is unlikely to be anytime soon.

1. The beaming of power from SPS to the surface with microwaves can be
tricky because various molecules in the atmosphere could absorb the
microwaves which would make the atmosphere hotter, not cooler.  You could
manage this by selecting microwave frequencies that don't have this effect
but I don't know what the frequencies would be given the materials one would
have on hand for the building the transmitters and receivers for the power.
This entire area would require some research.
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