An Industry for the Moon, Good Economics

[rogers_buck]

Looks like the earth may be overheating with little prospects for cooling things down in the short term. Perhaps a good industry for the moon will be the raising of dust clouds. By creating a band of dust in lunar orbit some of the flux falling to the earth would be reflected away. The moon could be earth's air conditioner.<br />

 

[owenander]

I think the moon would be too far away and couldn't create a big enough cloud to make it worth the high cost, plus the moons gravity is too light to actually maintain anything in orbit like that I think, but not sure.

 

[rogers_buck]

Nice thing about reflectance is distance doesn't matter. The size and density of the dust band is what is important. The moon has lots of dust but at such a large distance from the earth the volume of the dust cloud would need to be huge, as you point out, to fill that volume. But perhaps the dust cloud can be more local to the lunar vicinity and simply shade part of the day in sync with the lunar cycle. Make for daily eclipses by increasing the diameter of the moon 10000 times over.<br /><br />The dust would likely co-orbit with the moon and fall back to its surface or get carried away by the solar wind.<br /><br />

 

[owenander]

When I mentioned distance, it wasn't in that aspect it was more geared towards since the moon is so far away (and moving farther) you would need to create a very large disk in order for the coverage to actually make any difference because of the angle. Think of an eclipse, usually a very limited area is even fully covered, if you even had a dust disk around the moon twice the size, the 'eclipse' would only cover 60 miles of the earth (as opposed to somewhere in the ballpark of 30 for an ecplise).

 

[derekmcd]

I think a solar eclipse casts a shadow (umbra) around 170 miles in diameter, not 30. I'm not sure, but I think the umbra is that size because the angular size of both the moon and sun are the same. If you doubled the size of the moon, I believe the size of the umbra would more than simply double... I could be wrong on that, though. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[rogers_buck]

Yes, but fortunately it wouldn't need to be all that dense providing it had good optical depth. You could use some kind of a dust chucker (perhaps electrostatic) to launch the dust from the surface, and then a laser to shape and direct the clouds. You could replicate a large number of the dust chucker stations accross the lunar surface.<br /><br />There is serious money that could be made available for a project like this if the basic idea is sound. Carbon sequstration is expensive, hurricane damage is expensive, failed crops are catestrophically expensive, etc. The merits of this idea are that it can be deterministic with respect to investment/results where others have large margins of error. So many parts per cubic cm moondust results in a deterministic reduction of solar flux.<br /><br />I also like the idea because it solves one big problem with respect to commercializing the moon - the cost of goods transported. Like off-planet power production the "product" is delivered at the speed of light.<br />

 

[nyarlathotep]

Only problem with this idea is that failed crops and hurricanes aren't caused by global warming.

 

[rogers_buck]

The effects of global air conditioning would be global felt and there would need to be global agreement as to cause - effect and correction. The self serving interests that currently take issue with the dangers of global warming would likely change their position if a fix such as this were available that would still let them operate in the black. We need to buy a few decades to fix these problems technologically, and dust chucking might be a good way of buying that time...<br /><br />

 

[owenander]

Frankly, the only problem with global warming is that islands go underwater, the benefits make all the tundra in greenland, russia, and canada farmable. It'd be much worse to go into another ice age.

 

[nyarlathotep]

>"the benefits make all the tundra in greenland, russia, and canada farmable. It'd be much worse to go into another ice age."<br /><br />The major benefit is shipping routes through canada.

 

[rogers_buck]

You guys are applying linear scaling to a chaotic system. If the tundra thaws it produces enormous quantities of greenhouse methane. Tick. Methane is a killer greenhouse gas (see Titan) and further warms the oceans. Tick. The warmer oceans move outside the phase stability realm for subsea methane ices and massive upwellings of the trapped gas bubble to the surface. Tick. The earth heats even further melting the ice sheets making the polar regions less refelctive and flooding habitable coastline worldwide. Tick. The ocean currents alter or cease because salinity changes and temperature normalization effects. Tick.<br /><br />The geologic record shows abundantly that huge climatic swings in the earths temperature are accompanied by mass extinctions. We humans aren't tied to specific environments, but the suggestion of migrating populations portends warfare, famine, disease, etc..<br /><br />Far better to send a few billion to rogers_buck et al so we can build our automated dust chuckers.<br />

 

[nyarlathotep]

>"We humans aren't tied to specific environments, but the suggestion of migrating populations portends warfare, famine, disease, etc.."<br /><br />We're talking about a 500+ year timescale for global warming effects. We've only had industrialisation for 100 years, and look at how that alone has altered populations, famine, warfare and disease. <br /><br />Perhaps in the next decade we genetically engineer new phytoplankton and coccolithophorids to more efficiently sequester atmospheric CO2 and produce dimethyl sulfide? Seed the oceans with a little iron, bobs your uncle, global warming solved for only a few million dollars a year.

 

[rogers_buck]

The timescales for damage from global warming are not on the scale of hundreds of years according to widely held opinions and models. The fact that global cooling was only recently discovered and found to have offset the warming trend by as much as 2C has raised even more red flags. The timescales for major climatic disruptions that have been investigated in ice cores and other geologic features show that massive climatic changes occur quite rapidly, on the scale of decades. This further demonstrates that chaotic stability is behind every climatic epoch.<br /><br />But, I don't really want to debate the merits of global warming models here but I will embrace your example as a programatic aspect of the topic of this thread. A dust chucker would only be possible if everyone who could stop you from deploying the system agreed upon the need for it and its application. That's all politics after all, and if there isn't a political will there won't be a program.<br /><br />The concept I would like to focus on here assumes that we need to shade the earth and all are in agreement. Once that point is reached, it is my conjecture that there will be an economic boom for lunar dust chuckers. It isn't as romantic as the buffalo heards and stands of virgin timber that opened up the west, but it could have significantly more economic rewards without shipping anything back to earth. Apart from lunar power generation, I haven't read or heard any discussion of this kind of lunar economics.<br /><br />Not to put too fine a point on it, but if you consider the role the moon has played through time absorbing some of the meteor strikes that would have clibbered the earth, you could come up with an economic value for the moon. This is the same kind of economics, only humankind has to expend some effort to reap the benies.<br /><br /><br />The physics behind

 

[nyarlathotep]

>"The fact that global cooling was only recently discovered and found to have offset the warming trend by as much as 2C has raised even more red flags."<br /><br />The first red flag it raised was that the computer model was broken. The refusal to supply source led to more flags. The ICC now think that the number is closer to 0.6C. <br /><br />Shade doesnt necessarily have to be provided with a trillion dollars worth of moondust, we can just as easily provide it with moderate increases in dimethyl sulphide production. And DMS can be varied seasonally. If we kick up too much moondust, we're stuck with it for millennia.

 

[j05h]

The "dust chucker" is interesting, but at what cost? I'm not talking monetary, but the toll this added dust will cause to our in-space infrastructure? If you are throwing dust off the moon at near-escape velocities, it seems like a significant portion will eventually intercept GEO and the satellites there.<br /><br />The cure might be worse than the disease. It's an interesting, out-of-the-box idea that's worth exploring, but it sounds a lot like polluting cis-lunar space. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[rogers_buck]

Humm, your dimethyl sulphide oxidizes to sulfur dioxide and winds up falling as acid rain... Dead trees, more CO2.<br />

 

[rogers_buck]

The cost of infrastructure is astronomically high. That is what is keeping us on this planet. If there were gold in them there hills that would support a profit marging proportionate to the risk we would be all over space. If the dust chucker has merit it is in directing economic thinking away from material comodities to an abstracted economy.<br /><br />The technical and engineering aspects are enormous problems to consider. The basic physics behind the idea may also be impractical. We tend to speculate here (me included) without sanity checking ideas for order of magnitude soundness. Having said that, let's just pretend for the moment that all the engineering challenges have been solved and the physics is (of course) sound. Let's assume that through operation of the system and various control systems like moon based high power lasers, the system can control the earth's weather. If we make those assumptions then we can look at the budget for the project.<br /><br />1) Cost of hurricane damage over the lifetime of the system,<br />2) Cost of crop failures do to la Ninya and el Ninyo events,<br />3) Cost of ecological damage from homogenization of climatic zones,<br />4) Cost of super-Kyoto type emergency measures,<br />5) cost of desertification.<br /><br />As a total, these factors provide a multi-trillion dollar cost/benifits opportunity. The biggest economic boom in human history without shipping a single widget or nugget of unobtanium.<br /><br />If we became even more highly skilled in the art of weather control, it is conceivable that deserts could be returned to earlier epochs of greenery. If the dust chucker could be used for planet asteroid defence an even larger budget could be projected.<br /><br />The dust chucker is simply a different way of looking at the moon.<br />

 

[nyarlathotep]

>"Humm, your dimethyl sulphide oxidizes to sulfur dioxide and winds up falling as acid rain"<br /><br />Phytoplankton already produces about 25 million tonnes a year. I fail to see how increasing this by a few million tonnes extra would hurt.<br /><br />And quit peddling that stupid hurricane theory. The National Hurricane Centre has data which clearly shows that neither the intensity or frequency of hurricanes has increased in the last half century.

 

[j05h]

> The cost of infrastructure is astronomically high. That is what is keeping us on this planet. If there were gold in them there hills that would support a profit marging proportionate to the risk we would be all over space. If the dust chucker has merit it is in directing economic thinking away from material comodities to an abstracted economy. <br /><br />I'm not talking about future lunar infrastructure, but satellites that are already in orbit and useful. What is more a part of the abstract economy than communication and GPS satellites? <br /><br />I'm extremely skeptical about maintaining dust cloud integrity and keeping it from sandblasting GEO. New economics that make the moon profitable would be great but not at the expense of cis-lunar space. Nylathorp's iron-seeding is fundamentally simpler, as would be spreading aluminized Mylar on mountains to increase albedo. Almost any Earth-based remedy will be cheaper. Heck, if you have the tech to manage aerosols with lasers, it'd probably be cheaper to use ground-based lasers to hustle upper atmosphere particles around.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[rogers_buck]

I would imagine that the dusted zone would be an elipse with its closest approach being just beyond lunar orbit. You'd need to leave some room for the solar wind to blow your dust cloud away without disrupting my Dish Networks or sand blasting the ISS.<br /><br />However, the dust cloud wouldn't need to be an Arizona dust storm, It could be extremely sparse so long as it had sufficient optical depth to it. You probably wouldn't want to fly through it in your underpants, but a reasonably robust spacecraft should make it through. Maybe on the order of the plunge through Saturn's rings by Casini, less than Stardust's trek through the comet tale I would think.<br /><br />

 

[Boris_Badenov]

How much light would be blocked by how much dust? How much light blocked creates how much of a temperature drop? How much of a drop in temperature does it take to freeze the oceans all the way to the equator? I’d kind of like these questions answered before the SDC team gets started on this project.<img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[rogers_buck]

How much dust depends on the desired optical depth and foot print. This in turn depends on the desired temperature drop back on earth. This in turn depends on the duty cycle for the dust occultation. The duty cycle is a parameter picked up from feeding back the orbital dynamics of the dust cloud. Which in turn feeds back into the required optical density. Not the easiest problem in the world to solve when your not getting paid to solve it.<br /><br /><br />

 

[nyarlathotep]

>"How much of a drop in temperature does it take to freeze the oceans all the way to the equator?"<br /><br />Considering that reaching equilibrium would take centuries and that we have absolutely no way to quickly remove the dust, this is a VERY important question. How do we know we're not going to overshoot our desired temperature and turn the planet into Hoth?<br /><br />If Rogers turns the planet to Hoth, first dibs on using his carcass for warmth.

 

[rogers_buck]

What do you mean by reaching equilibrium? There may be no such thing. This would be somewhat akin to scaring the butterfly in Beijing to make it flap its wings. Before attempting this at home you had better know what you are doing...<br /><br />I'm not convinced the dust cloud would be so ephermeral. I think it would require constant replenishing. You can look at what happens to a comets tail to see why. There may also be longevity desinged into the dust clouds orbital dynamics.<br />

 

[josh_simonson]

The climate has been regularly changing +/-5-10'c for the last million years or so with the ice ages, and that isn't going to stop. Wether we address anthropagenic climate change or not, we will eventually have to deal with natural climate change as well. This demands and artificial solution that works both ways, warming or cooling the planet or regions of the planet at will to maintain an optimal climate.<br /><br />Ice ages have been very regular, and we're due to begin the next one sometime in the next 2000 years. It'd be foolish to spend trillions to address global warming with an inflexible system that can only address anthropagenic effects (like CO2 emission cuts) only to be faced by a new challenge with similar economic consequences. We should fix it right the first time. <br /><br />Space dust is not the answer since it can't easilly be cleaned up when the climate slides the other way. Large controllable mirrors would work better. The least expensive options right now involve dispersing non-permanent agents into the upper atmosphere.<br /><br />Local solutions are also possible, we've seen the temperature in cities rise due to all the asphalt absorbing more heat than usual, and making areas more reflective has the opposite effect. Laying down huge areas of mylar in the western deserts and salt flats could significantly cool those areas and produce more rain, ect.