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Giant space umbrella tethered to asteroid could protect Earth from climate crisis, study says
(www.independent.co.uk)
Everything to avoid doing the most obvious.
this post was submitted on 04 Aug 2023
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Nuclear?
- Find asteroid at L1 Lagrange point, which is unstable, meaning objects need to burn fuel to stay there for prolonged periods of time
- Put giant sunshade on it directly facing the Earth
- Sunshade acts like the largest solar sail in existence, making station-keeping useless
- Because L1 is an unstable equilibrium, solar radiation immediately blows asteroid away from the Lagrange point and directly into Earth's gravity well
I'm sure nothing can possibly go wrong with this plan.
While this is still obviously not a realistic solution to the damage we're doing to our climate because it still involves launching 35,000 tonnes of material in to space and moving 100 times that much to the right location, the solar sail thing has been accounted for in the paper. Basically you stick it slightly closer to the sun than the actual L1 point, where the force from solar radiation balances out the slightly higher pull of the sun's gravity
If only we had re-usable rockets, we could save humanity.
Let's assume SpaceX's Starship starts working flawlessly tomorrow. It is apparently intended to get 100 tonnes to the moon, but it needs a second launch to get fuel in to orbit to reach higher energy targets. So we're looking at two launches per hundred tonnes. Assuming flawless operation and literally no weight for equipment to actually assemble the stuff once it's at the location, that's 700 maxxed out Starship launches just to get the shield in place.
After that, you've still not even started on getting the 35 million tonnes of counterweight in to position. And yeah, it helps if you only have to get 35 million tonnes of rock out of the moon's gravity well instead Earth's, but you still have to move 35 million tonnes of stuff. Getting 35 million tonnes to lunar escape velocity requires equal energy to 1.6 million tonnes to Earth's escape velocity (which would be 32,000 Starship launches), and that's before you account for having to get your rockets, fuel, and infrastructure to the moon in the first place.
After that, you still need to stop blanketing Earth in greenhouse gases or you need to keep making the shield and the counterweight bigger to compensate.
This just isn't happening on any realistically helpful timeline. This is maybe helpful to just start repairing some of the damage in a scenario where we fail completely.
Moon’s got no atmosphere so you can build a railgun to launch containers.
They still have to be caught, which will require a shit ton of fuel, but at least you cut it in half.
Maybe you can get the containers to collide. You shoot them to the lagrange point in opposite directions. All the energy could be input via railgun on the moon, then removed via well-timed collisions. Big cumple zones of foam or something would be necessary, unless you use stabilized magnetic repulsion. Heck they could slow each other down with laser beams if they had a big enough collector.
Then your engineering hurdle isn’t “How to produce fuel for 32,000 starship launches”, but rather “how to catch a flying container full of material” and you balance the momentum by sending other containers around the other way to meet it and get caught going the other direction.
And how to build a railgun on the moon for launching cargo containers. Not my idea, incidentally.
Who knows, it might even be good for our species to have some huge stretch goal to be pursuing in space.
Maybe the aliens will let us borrow some flying saucers and we can have it done in a month.
I think when the solution is "built a giant railgun on the moon and also a system to catch millions of tonnes of railgun shots a million miles from Earth," it's pretty reasonable to say that you've strayed outside the realm of solutions we can have ready on time.
At the end of the day, none of the things you mentioned are things we can actually reliably do at the moment. ESA successfully intercepted a comet a few years ago and it barely worked; your plan effectively asks us to do that but millions of times with a far smaller target and we also need to make the comets first. Oh and also once we've done that, we also need to assemble tens of millions of tonnes of material in space.
A railgun on the moon is a good idea for future space colonisation, but for climate change we unfortunately need to fix the problem now and definitely can't wait for an experimental lunar megaproject to be just one component of a temporary fix.
We already have a huge stretch goal to reach for as a species. It's on Earth, and it is powering our society without fossil fuels. We even already have tech to do the vast majority of it, and best of all once it's done it actually is done, unlike the space shield. We still need to do it eventually even if we magic the space shield in to place tomorrow. We just seem to be collectively deciding that it's best to kinda put it off as much as possible.
We keep stuff in unstable orbit all the time using thrusters.
We can easily counteract the solar wind with a reasonable amount of thruster fuel.
And remember kids: when the fuel isn't being burnt on earth, and it's being burnt outside our planets stuff. Pollution is no longer our problem.
It's a technological antisolution.
Thank you for sharing this!
You're very welcome! I'm so glad you enjoyed it.
This line represents one of my biggest peeves with political thinking in general:
A Technological Antisolution is a product that attempts to replace a boring but solvable political or social problem with a much sexier technological one that won’t work.
The assumption that because there’s a “political or social” problem, then it must be solvable.
Why? “Because if everyone just did X …”
People skip over political problems. They model humanity’s political and behavioral inertia as zero, and they don’t treat it as an ecosystem.
So many “political or social” solutions are assumed to take zero energy. The only reason a “political or social” problem won’t work is those “durned right wingers”.
What this implicitly fails to realize is that building an enormous solar sail is many orders of magnitude easier than changing the behavior of every human.
We need to stop thinking of things as “practically solved” just because “all” that would have to happen is some huge shift in the behavior and organization of human society.
I also created lots of solutions to the worlds problems sitting around getting high
I know man. We’ll just accelerate the planet and move it into a higher orbit!
None of the geoengineering solutions address the other major issue with our fossil fuel usage, which is ocean acidification. Even if we could just lower the temperature, lots of the CO2 pumped into the air gets absorbed into the oceans, like in a bottle of soda, making it more acidic. When this happens, it makes it harder for all the life at the bottom of the food chain to form, causing a mass die off at the base. If things get bad enough It could lead to the collapse of the food chain and we would just starve to death.
Excellent point. And if we put up a big space mirror, and then solve the CO2 problem to get ocean PH back to normal, now our lower solar incidence plus normal greenhouse gas levels will equal temperatures way too cold.
Imagine Keppler syndrome kicks in as a result of building it, and it causes an ice age down here and we lose contact with it and can’t move it.
Now we’re an ice ball with a sky cage we can’t escape.
Giant space umbrella tethered to asteroids could also be a super weapon capable of melting enormous swathes of enemy territory.
In fact, any technology capable of stopping global warming can be turned into a super weapon. Including whatever techniques might be used to alter human behavior to reduce footprint.
Or, we could go to the other side of the sun and turn off the enormous fan, thereby stopping the hot solar wind.
SIR, the fancy word is parasol. A World Parasol. Maybe with some nice lace.