Re: Methane threatens to bake humanity like Turkeys in an Oven


"Ian Parker" <ianparker2@xxxxxxxxx> wrote in message
news:1170604222.817336.259970@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On 4 Feb, 12:02, "George Dishman" <geo...@xxxxxxxxxxxxxxxxx> wrote:


Von Neumann machines are irrelevant since there is no
local raw material for them to use to create copies of
themselves or the flatpacks in situ. What you need is
a lifting system to get the flatpacks into orbit and
just a single assembly robot to connect them together.

What about the Moon/asteroids. You dont need a big lift on the Moon
and on asteroids hardly any. In fact you could take off with ion drive
alone.

Ion drive to lift from the Moon? Not even close. From
a small asteroid with microgravity perhaps but you then
still have to get it to L1. In fact what ou would do if
the manufacturing technology was available would be to
land a mass driver on the asteroid, push it to the right
location, then start processing at that point. You don't
want to be moving a vast thin plate around and coping
with the tidal forces as it passes the Earth.

What I propose is similar to George Bush's return to the Moon -
only with one difference - No astranauts. The moror skills of an
astronaut can be replicated completely by machines.

We are nowhere close to that level of technology. The
rovers on Mars are the best. If there was an astronaut
there, he could blow the dust ou of the failed motors
and get them working again. The rovers can't even do
that and if they could it would still take a human
operator to control it remotely. A computer could
easily detect the motor had failed but wouldn't be
able to work out why or how to repair it and again we
are many years away from anything like that capability.

OK one might say
can you automate everything.

You might, the rest of us have a much better grasp on
reality.

At present it is a question of economics.
You will say it it cheaper to employ a charlady rather than a machine
- but when your charlady cost $138e6 a week. The current price for
space tourism.

I suggest you start by calculating the area needed,
and then mass of a structure with sufficient strength
to remain fairly rigid given the tidal forces at L1
and hence the mass.

Given that we can barely afford
to repair the Hubble, the idea of lifting that amount
of mass to L1 is ludicrous.

Hubble is the NASA establuishment. The whole principle of the VN
machine is once you have sent the seed you can replicate. The whole
idea is to build a self replicating entity.

Out of what? The closest we have got so far is to assemble
blocks that have already been constructed:

http://www.news.cornell.edu/stories/May05/selfrep.ws.html

That is vastly different from sending a machine to an
asteroid. The simplest chips in those blocks took billion
dollar fabs to manufacture and that is after the silicon
and dopants have been mined, refined and grown into crystals.

We will achieve what you are considering eventually using AFM

http://www.almaden.ibm.com/vis/stm/atomo.html

http://research.chem.ucr.edu/groups/bartels/

but we are _many_ decades away from using it for macroscopic
objects.

The NASA establishment
seems to believe in something like "Intelligent Design" (As does the
boss) Astraunauts seem to be enddowed with the kind of "vital force"
postualated by (some) 19th century chemists. My contention is that
anything an astranaut can do a machine can do - probably better.

Go ahead then, see if you can get farther than Cornell.
Or just publish the drawings for a self-contained machine
nanotech machine that can make a copy of itself out of a
lump of raw asteroid using AFM without any preprocessing.

As far as total amounts are concerned. This has in fact already been
discussed by other people (see sci.space.policy) 1/10 of the area of
the Earth's circumferance has been discussed. In the case of VN the
weight is largely irrelevant. A non VN Earth transportable solution
with mirrors weighing 55kg/km^2 has been proposed. Rigidity is not in
fact a probem. If you did want a rigid structure you would spin it.

Nope. If you spin it face on between the Earth and Sun
today, it is edge on in three months :-( It will spin
once a year on an axis perpendicular to the ecliptic.

Think what the forces would be if a CME hit one side of
the shield. Has anyone calculated that or the strength
needed to avoid destruction? Your are talking about an
emormous mass to make this survivable.

The spped of rotation required would by of the order (minimum) of one
revolution per YEAR. Let's say one revolution every month to keep the
structure really taught. We would have a circumferance of some
12,000km. This works out at rather less than 20km/h. The tensile
stress is proportional only to velocity.

The _logical_ solution is simple, reduce coal and oil
production by 5% per year and let market forces raise
the price to the point where renewable alternatives
like wind power for electricity and bio-fuels for
transport and chemical feedstock become viable. That
would give a huge boost to the agriculture industry
in many of the developing countries which would be
hardest hit by restrictions on fossil fuel and could
be backed by technology transfers to give them the
processing capabilities.

That is the whole point about methane. This will not work.

The point is to reduce the heating below the threshold
for the positive feedback in the methane release to
overcome the natural negative feedback in the rest of
the biosphere.

Fossil sources will run out eventually so it's a bullet
we will have to bite sooner or later. Of course, while
it is a logical solution, it is as feasible politically
as your sunshade is economically.

It is economic. Once a seed is developed it is fire and forget (not
quite you still need to control it).

Sure, but we won't have that sort of technology until late
in the century at best - too late for sure.

BTW - Blair has commissioned a think tank which discussed "robot
rights". How he imagines that strong AI is possible when he rules out
weak AI solutions for the same data I really don't know. Nelson
planted trees in the Forest of Dean. They were to have been cut down
in 1914. Jutland was fought with steel ships.

Go ahead and produce your machine if you think you can, but
in the meantime something has to be done about protecting
the planet and dreams of replicators won't do it in time.

George


.

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