These scientists want to put a massive 'sunshade' in orbit to help fight climate change

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So, given that the L1 orbit is dynamically unstable, and the solar pressure tends to move the shade toward Earth, what is the probability that this whole thing would someday depart from its L1 orbit and eventually cross Earth's orbit and Earth would crash into it? What would the effects of such a crash be on Earth?

Yes, it is thin and a square meter weighs very little. But, it is also enormous in diameter. So, how much would the whole thing weigh? And, as it approached Earth, how would it collapse in Earth's gravitational field? What would it do to our other satellite infrastructures? What effects would it have on the Moon? What effects would reentry have on our atmosphere? How much heat will be radiated to the surface if this shield ends up "burning up" on reentry?

Scientific daydreaming can be useful. But hard engineering questions need to be answered before anybody tries to turn such dreams into reality. And, those questions should not be limited to how to do it and how much it will cost for how much benefit. Engineering assessments need to be made about what can go wrong and what the consequences of those possibilities are. It is not just a cost vs benefit decision, it is a risk vs benefit decision.
 
Jan 28, 2023
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There would have to be frames to keep the shape and to fit engines to maintain position and orientation, fuel and oxidizer tanks, or some kind of propellant that could be electrically heated. For power supply, the canvas can also have a photovoltaic layer. In general, there would be a really huge table, given the dimensions. I can't even imagine just building all of the above and how it would be delivered, even with thousands of launches of the heaviest rockets we have today. For price suggest not less of whole GDP of the planet Earth for 2 years.
 
I have seen proposed statite orbits that use the carefully directed reflections of the sunlight to control attitude and position, without using propellants. Energy for control systems would be solar. The reflectivity would need to be controlled by some sort of mechanism that might be electrical effects on materials used to make the shades/sails. By controlling reflection vs absorption, sail shape can be modified, and shape controls the forces from reflections at various parts of the sail/shade surface.

So, continuous use of chemical or nuclear power plus expendable propellants would be avoided, as would the cost of launching those weighty components.

However, what would be the effects on such a shade from collisions with things like orbiting asteroids and clouds of "comet tail material" such as we frequently see here on Earth as meteor showers? Can we really control such a huge surface? Does the answer take into account the known collision intensity for various sizes of solid particles that cross the orbit of the shield? What would the effects of a solar mass ejection be on the shade system - damage to sail material, damage to control electronics, perturbation of shade shape, perturbation of sail orbit?
 
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There is no way to allow drift, as with terrestrial sailboats. In a drift, the ships shift their position, although less than in the downwind movement. In space, however, the motion is not two-dimensional on a relatively flat surface...I don't think it is at all possible to do without actively and constantly adjusting the parameters by using engines. We do not yet handle other possibilities for the target, such as those described in the works of fiction, "trajectory beam", "anti-gravity", "manipulated force fields" and so on. Not even having nanorobots to take care of construction, meteorite damage repairs, and anything else needed to build and maintain it in working order.
 
Regarding your post about sailboats and "drift", see https://en.wikipedia.org/wiki/Solar_sail , particularly where it says:

"Robert L. Forward has commented that a solar sail could be used to modify the orbit of a satellite about the Earth. In the limit, a sail could be used to "hover" a satellite above one pole of the Earth. Spacecraft fitted with solar sails could also be placed in close orbits such that they are stationary with respect to either the Sun or the Earth, a type of satellite named by Forward a "statite". This is possible because the propulsion provided by the sail offsets the gravitational attraction of the Sun. Such an orbit could be useful for studying the properties of the Sun for long durations.[32] Likewise a solar sail-equipped spacecraft could also remain on station nearly above the polar solar terminator of a planet such as the Earth by tilting the sail at the appropriate angle needed to counteract the planet's gravity.[32]"

Diverting to sailboats for a moment, my actual experience sailing boats upwind, plus my background in aeronautics and physics, allows me to understand the interplay of forces involved. In that case, it is not the "reflection" of the wind, but rather "lift" created by the changes in pressure of the air flowing at different speeds in different places around the sail, which keep the sail in its designed shape and impart a net force on the sail that is somewhat "upwind" of the straight "downwind" direction. This is played against a similar force created by the boat's keel moving forward in the water at a slight angle under the boat, which imparts a "lift" force on the hull that is "upwind" of the straight downwind direction, and to the opposite side of the net forces from the wind on the sail. The boat responds to the combination of those forces it go upwind at an angle to the wind. (And, of course, the boat leans to one side because the air and water are causing opposing forces at different elevations, so gravity is also being used to keep the boat from simply laying over flat on the surface of the water.)

So, sailboats gong upwind are far more complicated to understand than the forces on a statitie, where reflected photon momentum is being used directly to counteract gravitational attraction in a vacuum with no aerodynamic or hydrodynamic forces, and no interface between fluids.
 
Jan 28, 2023
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Regarding your post about sailboats and "drift", see https://en.wikipedia.org/wiki/Solar_sail , particularly where it says:

"Robert L. Forward has commented that a solar sail could be used to modify the orbit of a satellite about the Earth. In the limit, a sail could be used to "hover" a satellite above one pole of the Earth. Spacecraft fitted with solar sails could also be placed in close orbits such that they are stationary with respect to either the Sun or the Earth, a type of satellite named by Forward a "statite". This is possible because the propulsion provided by the sail offsets the gravitational attraction of the Sun. Such an orbit could be useful for studying the properties of the Sun for long durations.[32] Likewise a solar sail-equipped spacecraft could also remain on station nearly above the polar solar terminator of a planet such as the Earth by tilting the sail at the appropriate angle needed to counteract the planet's gravity.[32]"

Diverting to sailboats for a moment, my actual experience sailing boats upwind, plus my background in aeronautics and physics, allows me to understand the interplay of forces involved. In that case, it is not the "reflection" of the wind, but rather "lift" created by the changes in pressure of the air flowing at different speeds in different places around the sail, which keep the sail in its designed shape and impart a net force on the sail that is somewhat "upwind" of the straight "downwind" direction. This is played against a similar force created by the boat's keel moving forward in the water at a slight angle under the boat, which imparts a "lift" force on the hull that is "upwind" of the straight downwind direction, and to the opposite side of the net forces from the wind on the sail. The boat responds to the combination of those forces it go upwind at an angle to the wind. (And, of course, the boat leans to one side because the air and water are causing opposing forces at different elevations, so gravity is also being used to keep the boat from simply laying over flat on the surface of the water.)

So, sailboats gong upwind are far more complicated to understand than the forces on a statitie, where reflected photon momentum is being used directly to counteract gravitational attraction in a vacuum with no aerodynamic or hydrodynamic forces, and no interface between fluids.
If you follow link to "statite" will read this:
No statites have been deployed to date, as solar sail technology remains in its infancy. NASA's cancelled Sunjammer solar sail mission had the stated objective of flying to an artificial Lagrange point near the Earth/Sun L1 point, to demonstrate the feasibility of the Geostorm geomagnetic storm warning mission concept proposed by NOAA's Patricia Mulligan.[3]
So, we don't have any practical experience if it would actually work. Only theoretical productions. From that point to eventual full-scale implementation, if it turns out to be a working concept, is again at least 60+ years away, as I've written. No matter how much we tend to brag, and even that we are capable of self-destruction, such a project is far beyond the present capabilities of our entire civilization.
 
I agreed from the beginning that it isn't something we can just do with available technology.

And, I also pointed out that it may have risks that are unacceptable, even if we can develop the technology to do it.

I don't have a problem with some people studying the concept, so long as it gets some realism before the study gets into substantial expense.

I think statites will probably be developed, but I am not convinced that they will be robust enough and useful enough to warrant significant deployments.

I think it would be ridiculously stupid to bet on the success of any sort of orbiting sunshield as an excuse to not deal with the climate problem sufficiently in some other ways. And, if we fail to do so in some other way on a much more rapid time-line than I expect an L1 sunshield to require, I think we will have so much damage to on-Earth infrastructure that we will probably no longer have the wherewithal to implement an L1 sun shield, anyway.

All of that aside, I don't see how an L1 sun shield could be cheaper or faster than on-the-ground CO2 removal technologies. And, what is the CO2 emissions cost of building and launching all of that stuff to L1? We are still having trouble getting a net CO2 emission reduction from building electric cars.
 
Bill, there are lots of things like that we could do, but aren't even talking about.

For one thing, we have a lot of parking areas that are paved with black asphalt, on which we park our cars in summer and then come out and turn on their air conditioners to cool them down, at the expense of burning gas or, at best, using EV range. Meanwhile, we are taking open fields that used to be crop lands and turning them into "solar farms".

How about we put "solar roofs" over shopping area parking lots instead? Use the solar power to top off the parked vehicle batteries and the excess to light the stores, at least, not to mention run just about everything else in the daytime? Plant some trees instead of planting solar cells on ag lands, if we don't want to use that for crops.

Cities would benefit most from white roofs. And, maybe cisterns to catch some of that rainwater that is producing dangerous flooding? More suburban and rural buildings could use black roofs in the winter, shaded by deciduous trees in the summer. That is what my family has done for generations.

Where I live, we have plenty of empty commercial buildings, some not even very old. But instead of "repurposing" those, we are still permitting crop and forest lands to be turned into more buildings with sprawling parking lots.

All of the planning seems to be about short term profits, especially for folks who already have a lot of money to invest, with minimal initial outlays. Long-term effects aren't in their picture, especially if somebody else needs to pay for them.

But, the people who are focused on zoning rules seem to be only interested in prohibiting new gas furnaces and stoves - very prematurely in my evaluation - because those things are more energy efficient and CO2 emission reducing than electric versions - until we get nearly all of our electricity from sources that do not emit CO2.
 
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This also seems like something every country on the planet needs to be onboard with. Start blocking the sun without everyone's approval will cause conflict.

The environmentalist need to give a little. Modern day nuclear energy tech is clearer than the old days and can achieve the goal of dropping greenhouse gasses today. On top of that a good portion of the US can support solar at the home, then only use the grid at night, without the need to have off-grid batteries unless people want to buy them. That should also reduce greenhouse gases significantly.

However there is still the issue of energy corporations still wanting their record profits and helping developing nations make the switch. The biggest hurdle is getting nations who don't care about this to make a change. Still seems easier than building something that blocks the sun.
 
"However there is still the issue of energy corporations still wanting their record profits." - Raygun

Publicly held energy companies, just like every company, have a legal duty to obey the law. They also have a fiduciary responsibility to the shareholders to maximize shareholder value. If they don't do that they can be sued. There is nothing wrong with "record profits" as long as they play by the rules. In the capitalist system, record profits attract record invesnment capital, thus increasing suppliers and lowering costs.
Artificial constraints on profitability result in shortages and high costs. I remember when Nixon froze prices in 1971 and instead of paying for heating oil at 6 cents a gallon I had to pay 30 cents.
 
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I always wondered about thermal chromatic paint/sufacing. Turning reflective above 70F and absorptive below hopefully including as much of the Sun's spectrum even beyond the visible.

I wonder that home/building design doesn't include vents to attic and crawl spaces that open for cooler night air in summer and warmer day air in winter.

People operate on a largely invective manner without much reflection where rational consideration might come into play.
Monkey see, monkey envy.

The cheerleaders for the most irrational, reckless unaccountable behavior have been self labeled 'conservatives' which is ridiculous.

As for those hard scheming fossil fuel companies,
should the explicit corporate subsidies from taxpayers be repaid before they walk away with record profits?
 
Yes, but somebody has to pay for making infrastructure environmentally friendly, and neither investors nor tax payers nor rate payers seem eager to do that.

At this point, the laws which require U.S. companies to use environmentally friendly processes have resulted in large portions of U.S. manufacturing leaving the U.S. for China, India and other places where it is still OK by government regulations to make a polluted mess. (A similar pressure to export manufacturing results from similar laws that require U.S. manufacturers to treat workers well, with expensive benefits.)

Governments tend to try to sweeten the initial steps for transitions to things like solar power with subsidies, but, those are not affordable to cover the whole transition. People will need to pay more, and that makes the transition less popular and slower to implement. The U.S. debt is already 33 trillion dollars and rising fast. That is over $90,000 per person, including infants just born, as well as retired folks. We can't afford to have the "government buy solar power for everybody". We are going to have to pay as we go, pretty soon now.

Oh, and the money you think you are saving by not buying gas for your electric car - you also are not paying the "gas tax" that is needed to maintain the roads you are driving on. There are already bills to tax electric cars, and heavily, based on their higher weight and thus greater wear on the roads and bridges.

And the U.S. doesn't get away with just paying to convert its own infrastructures to all -electric. The "poor nations" want the lifestyles the "developed nations" already have achieved, and will use fossil fuels to achieve it unless the "rich nations" subsidize the all-electric infrastructure for the "poor nations", too.

The climate problems cannot be solved by a bunch of rich people sitting under solar cells and eating a vegan diet in the U.S. while the rest of the world continues to do what it is already doing to "develop" itself.
 
Since putting a solar shade between the Sun & Earth would favor the summering hemisphere it would additionally reduce light & heat in Summer reducing seasonal energy demands,
While leaving the Winter hemisphere in total sunlight.

All provided it is feasible and reasonably safe.
 
"should the explicit corporate subsidies from taxpayers be repaid before they walk away with record profits?" - Questioner

I dogged that one down once and it turns out to not be a "subsidy" any more than any other corporation gets. What they are talking about is the oil depletion allowance. Oil companies pay a very large sum for the rights to drill on certain tracts. As they draw oil out, every year they get to deduct from their income a portion of what they originally paid. As the reservoir is depleted, they get to write off their expenses. This is no different than any business anywhere depreciating their assets.

But a more general principle applies - as long as they are obeying the law, I have no problem with them. If you don't like the oil depletion allowance, your best action is a strongly worded complaint to your local elected representative.
 
Addressing the effects but not the cause, by means that are too uncertain. Too expensive. Too late.

It isn't a plan, it is a thought bubble. We are somehow capable of developing the advanced technologies to do major construction in space in a timely manner - with mining moon and asteroids thrown in - but somehow it is mass production of better ways to make and store and use energy that is somehow so far beyond us that it is science fantasy? Have to tell the investors in mega factories that!

At the heart of the urge to find more palatable alternatives (to those invested in fossil fuels) is doomist assumptions that we are incapable of addressing the problem effectively by addressing our primary energy and are crying out for quick fixes that avoid addressing the emissions directly or urgently or can fix it later - despite RE as the means to displace fossil fuel use being the one area where we keep having our pessimistic assumptions overturned again and again.

VERY frightening? -

iu
 
It's pure speculation. And will probably not be necessary.

First of all this project and many others would take more than a decade. This is 12/23. If the projections I read are true, and India and China(and others) stay on schedule, by 12/33, these coal fired plants will emit more than all previous emissions combined. According to the numbers. Many say these numbers are dangerous. And will cause world wide problems.

If you require a reference, just watch the news. And read science research articles about fossil fuels. Take your pick.

By 12/33 we should all know if these "high" CO2 levels are really a danger. And what effects to expect from it. We have all been bombarded with doom and gloom. 10 years of un-presidented emissions should show us. Show everybody.

Thankfully, we should know before any of these modulators can be put in place.

I have seen, heard, read and been preached at of science predictions about climate and energy for the last 6 decades. Every one was wrong.
 
Ken, I sort of agreed with you, until the last part where you claim our pessimistic assumptions about displacing fossil fuels with renewable energy are "being overturned again and again".

The reality is that globally, we are still increasing our CO2 emissions, and all (I think) nations are not meeting previous pledges for reductions. Even the U.S.'s progress in electric vehicles and solar installations is "low hanging fruit" compared to doing the same in the rest of the world. And, we have reached the point in solar installation where not all of the energy that could be generated can be accommodated by the California grid - and so a lot of potential production is "curtailed" for grid stability reasons. It is going to take more transmission lines and more energy storage going forward.

A positive tend in a few parameters in the short term is no guarantee of ultimate success.

But I do agree that making an L1 sun shade is likely to cost more, be less reliable, and probably not be available anywhere near the needed schedule, compared to using on-Earth technologies that we know how to use. The problem is that we don't seem to know how to get them funded at the levels needed to meet the schedule promised.

Some of that is due to political ideologues insisting on their "perfect" solutions instead of pragmatic recognition that we have faster ways to make progress that are not their perfect ultimate solutions. I keep telling people that I will buy an electric vehicle that is the size of a small "crossover" (e.g., a Toyota RAV4) that gets 100 mile range on battery alone plus has an on-board generator that can extend its range by burning fossil fuel to run an on-board generator. That type of vehicle would allow most people to drive most of their miles on electric power only, and would obviate the need for them to also have a separate fossil fuel powered vehicle for things like extended trips, evacuations, power outages, etc. The technology is here to do that now - but nobody is building such a vehicle. But, if we could get them on the street now, as batteries improve, their all-electric ranges could be extended. And, because the batteries are smaller than full-electric, replacement would not cost so much that it kills any resale value. Maybe now that car rental companies and manufacturers are starting to scale back investments in all-electric cars, somebody might actually listen to the customers?
 
Do the public and future generations get a depletion allowance as the fossil fuel CO2 capacity of the atmosphere is depleted by fossil fuel products?
No they don't have expensive K st lobbyists.
Unmanaged free markets are degraded to government rigged markets by irrational profit agendas.

Profiteering has no consequences only in capitalist advertising fantasies.

Real Conservatives recognize consequences,
that irrational right wing nuts refuse to.
 
Questioner, there is no perfect system economic system - mainly because humans ourselves are not "perfect". We can't even agree on what a perfect person or system is.

Effects like depletion of environmental capacities are what economists call "externalities" because they are "external" to (not included in) the economic models that economists use to make economic decisions. Other professions just say their models are "incomplete" where certain causes or effects are not modeled.

What regulation is intended to do is to bring those effects into models as constraints. Mainly, they limit certain activities, or put costs on them by law, that in some ways reflect the population's concerns about the effects that aren't being modeled.

But, all of us imperfect humans have differing opinions about what is "fair" and what is not fair. So, there is a lot of disagreement on making such laws, including taxes, fines, etc.

And it should be obvious that we can't model things we don't realize are happening, nor make accurate models of things we do not understand completely.

So, people who have a system that is working for them in the short term are skeptical of proposals from other groups that will affect their short-term well being. They are being ask/told/forced to make changes in what works for them based on somebody else's "model" about how the future will develop with and without their proposed changes in the system. Given that all models are incomplete to some degree, it is not irrational for people to want some assurances that the changes they would need to make in the short term will really benefit them in the long term.

And it is an even harder "sell" to make people give up their well being now for the potential increase in the well being of others, later. There is so much conflict in the world already that "others" who "need" what "we have" usually get turned into "enemies". That is mainly an over-population effect caused by the reality, or even just the erroneous perception, that there is not enough of something to support the well being of everyone.

So, the real problem for humanity now is how to convince enough people to make some really major changes in the systems we are currently using. Remember, most are going to be skeptical when told that "the science says" something, because we know that "science" is based on incomplete models and have all seen some things turn out differently than predicted. In particular, we do not seem to be very good at predicting how humans will behave in the short term, as evidenced by the news headlines and the vastly different political positions taken in response by the leading political parties.

People are more agreeable to accepting opportunities than to accepting coercions. But, people are also skeptical of predicted future opportunities that cost them something immediately. That is why there are jokes about "buying that bridge in Brooklyn" and "water-front property in Florida".

So, to me, our real problem comes down to managing ourselves, because we are running out of options for managing our environment to compensate for our lack of ability to manage ourselves.
 
Feb 5, 2023
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Knock it off with this ridiculous "climate change" farce!!! Y'all are gonna wind up really screwing the pooch trying to alter the natural heating/cooling cycles of our planet. Just stop already!!!
 
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One problem is our society has rationalized that profits are a 'good' thing.
'Profits' are a derailment of the one to one correspondence between what it costs to produce something and what price someone pays for a product.
While i can accept small profits as a motivator to economic activity blindly accepting any degree of profit especially when there are extinction level ramifications is insane.
One problem with centralized government is it is 'one stop shopping' for corruption.
Self righteous sanctimonious rationales for that corruption get pretty absurd.

I accept that people's psychological stability is generally foundated on a belief in magic.
Magic religion.
Magic ideology.
Magic government.
Magic personalities.
Sadly many people are seduced with the silly notion that 'science' is simply the ultimate form of magic.
'A journal says' becomes sacrosanct.

Science is the conservative activity of correlating 'explanations', theories with evidence and logical deduction,
where possible.
Unexamined hearsay is anathema to that,
including parroting a published journal's headline 'pronouncement'.

Swallowing unexamined sanctimonious rationales for officiated economic corruption are gagworthy.
 
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Questioner, you seem to completely misunderstand what "profits" are.

Would you be willing to work for free, doing things for others for no benefit to yourself? They just provide the resources needed for you to work for free. I think you would want something in the way of remuneration for your efforts. Whatever that remuneration is would be profits.

What you seem to be against is profits from investments. But, those are really just transitions from work one has done previously to support work that others will do in the future, using money as the means of transmitting effort.

Clearly, it isn't a perfect system. But, neither is anything else humans have ever devised. Even within families, bad actors disrupt the processes. In nations, bad actors seek the power to misuse other people's efforts. It isn't just slavery or serfdom, it includes tax policies and other economic coercions.

But, that doesn't mean that human societies function without some sort of "profit" system to induce people to work collectively. Even supposed "communist" nations like the Soviet Union and China have had to introduce some profit motives to make technological advances needed to compete with the "western" nations. That is not "communism" in the Karl Marx economic sense - which really doesn't work because it ignores actual human nature.
 
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