Cheap method to cool the earth

This topic was mentioned in sci.space.policy
(How to Cool a Planet), but sci.space.tech is a
better forum for serious technical debate.

The review of nearly all ideas was published in:
http://www.rense.com/general18/scatt...rwithnotes.pdf

I am not ignoring extremely lightweight contraptions,
but there is some concern about their survivability
in outer space. Sometimes simple contraptions, like
like Mikhail Kalashnikov's AK-47 rifle are the best
ones.

Could we use the moon or its part as the earth cooling
contraption? Suppose that we drill a hole in the moon,
place a big hydrogen nuclear bomb at its bottom and detonate
the bomb. If we aim the detonation towards the earth,
the regolith, much of it fine dust, will either orbit
the earth or it will plunge into the earth's atmosphere.

Suppose that the detonation’s energy equals 50 megatons
(Tsar Bomba, http://en.wikipedia.org/wiki/Tsar_Bomba)

A megaton of TNT = 4.184 × 10^15 joules
(source: http://en.wikipedia.org/wiki/Megaton)

The escape velocity from the moon's surface equals
2.38 km/s (source: http://en.wikipedia.org/wiki/Moon)

The kinetic energy of the launched regolith is on
the order of: m*v*v, so the mass of the regolith =
50 X (4.184 × 10^15 joules)/(2.38 × 10^3 m/s)^2 =
3,693,242,002 kg = about 3 million tons.

3 million tons is roughly the amount of fine dust
in the earth atmosphere or in its orbit that is
needed to cool the earth a little. The Tsar Bomba
had the mass 27 tones. (It would be easy to make
much more powerful bomb of the same mass.) The cost
of making typical nuclear bomb is between $1 million
and $4 million (in 2005 dollars, source:
http://paxchristinewmexico.org/SERENE/factsheet.pdf)
It seems that the cost of making the big, 30 ton bomb
would be much smaller than the cost of launching the
bomb and landing it on the moon (about $300 million).

To avoid damage to existing satellites they would have
to be retrofitted with lightweight meteoroid (Whipple)
shields -- this is perfect job for telemanipulators.
Telemanipulator is also perfectly suited for digging
the hole in the moon.

I guess that the whole project would not cost more
than $1 billion. Can you imagine a cheaper method?

The dust would alter the spectrum of the sunlight --
everything would have yellowish tint and big fraction
of the ultraviolet light would be scattered away. This
means that the dust would reduce damage caused
by the hole in the ozone layer. Stars would not
be visible at night because the dust would scatter
mostly bluish light. This bluish night light would
probably eliminate the need for streetlights but it
could disturb wild animals.

On Mon, 03 Jul 2006 06:53:22 +0200, Andrew Nowicki
wrote:


Could we use the moon or its part as the earth cooling
contraption? Suppose that we drill a hole in the moon,
place a big hydrogen nuclear bomb at its bottom and detonate
the bomb. If we aim the detonation towards the earth,
the regolith, much of it fine dust, will either orbit
the earth or it will plunge into the earth's atmosphere.

To what avail. That would be dangerous and foolish.
I suggest you study some meteorology.
Just how much did you expect the earth to cool and
where? Do you think this dust distributes evenly?
Now imagine such a plume coming to wards the earth. It released by
detonating a bomb
so it all comes in one pulse. Thus it hits only one side of the earth.
This would indeed be cooled. In a small area to perhaps
-20 centigrade. Over the Brazilian rainforest's perhaps?
Then it spreads and causes chaos in the weather all over the world.
Is this supposed to counteract greenhouse warming?
Forget it! The dust settles after a couple of years
but the CO2 is still there. So all you get is a couple
of years of chaotic weather.


I guess that the whole project would not cost more
than $1 billion. Can you imagine a cheaper method?

Are you joking! A shuttle launch alone costs 500 million.
And you need 100 tonnes into orbit in order to get the bomb etc to the
moon. But then you also need to develop and distribute these
Whipple shields. There are hundreds of these. And the technology to
place them there doesn't exist. So several more 100 tonnes.

Of course the 50 billion or so this would cost is insignificant
compared to the cost of collateral damages on earth.

--
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Here is good, concise article about the moon dust:
http://www1.jsc.nasa.gov/toxicology/Taylor.pdf

It says that specific surface area of the moon
dust is approximately 0.5 m^2/g. It means that
one gram of the moon dust has the average surface
area of one half square meter. If one gram of
the dust is thinly dispersed in the outer space,
it will absorb and diffract about 0.1 square meter
of sunlight. One million tons of the dust will
absorb and diffract about 10^11 square meters of
sunlight, which is the equivalent of a square that
is 300 kilometers long and 300 kilometers wide.

The same article mentions magnetic method of sorting
the moon dust so that its particle size is reduced
and its specific surface area is enlarged. The very
fine dust would be less damaging to satellites, but
it would be quickly swept away by sunlight and solar
wind (like a tail of a comet). If this fine dust
enters the atmosphere, it will take a few months
before it is washed down by the rains.

Assuming it would work and the dust wouldn't be too radio active and
one could retrofit however many scores of satelites would be affected
and you didn't trigger some sort of "Space: 1999" scenario, blasting
Lunar dust into Earth's atmosphere would seem to be at most a one-shot
or N-shot thing and not sustainable - there is only so much Moon up
there and if you mess with it too much you will affect its orbit an/or
the Earth's tides and such.

Unless the root cause of Earth's warming is the quanity of sunlight
reaching the surface, it is also only treating symptoms.

rick jones
--
denial, anger, bargaining, depression, acceptance, rebirth...
where do you want to be today?
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

We need to understand the dynamics of climate system before we
*activiely* try to control it. I mean we know hardly a thing about long
term ocean mixing for example. Messing with a poorly understood
non-linear system is not a wise thing to do. You end up with complete
chaos.

The earth will change over time, we, like other species either adapt or
perish. However the climate changes we are talking about are not that
serious so......

all IMHO of course. mm no just IMO.

delt0r

Andrew Nowicki wrote:

contraption? Suppose that we drill a hole in the moon,
place a big hydrogen nuclear bomb at its bottom and detonate
the bomb. If we aim the detonation towards the earth,
the regolith, much of it fine dust, will either orbit
the earth or it will plunge into the earth's atmosphere.

There has been a proposal to blow up dormant volcanoes here
on Earth with nukes to release dust into the atmosphere to
cool Earth. It was mentioned in a novel by Risto Isomäki.
I don't know how seriously it has been studied.