So to maintain stable orbit (from my understanding) you will need to counteract that with a constant antinormal force, or else you’ll get pushed out of L1 and then go flying off.

You’re absolutely right, assuming the craft is on the L1 saddle point. The craft can, however, sit slightly sunward of the saddle point in a halo orbit. It wants to fall towards the sun (and enter a solar orbit) due to being on that side of L1, but you set it in the position it needs to be to balance the force of sunlight. There will be quasi-stable points in a halo orbits around the sun-facing side of L1 which could sustain a whole lot of these buggers.

KSP is great, but it only does two body physics (unless you’re using the Principia mod – never tried it). So you cannot simulate things like lagrange points there. The patched conics are a great first order teaching tool though, and KSP is great for that!

Solar sailing doesn’t require fuel, and can be truly solar powered. The IKAROS probe is a great example of this, and it was launched quite a while ago already. My favourite part of this probe was the liquid crystal panels that could change brightness and darkness electrically in order to steer by creating a differential absorption/reflection of sunlight. Clever stuff. It’s basically a steerable continuous thrust system that tacks against sunlight.

There’s also some untested methods that could potentially work here, like eletric tethers in the sun’s magnetic field – this stuff: https://en.wikipedia.org/wiki/Electrodynamic_tether – although I’m not aware of anyone that has done this calculation in the context of sunshields. And further outside the box, magnetic sails: https://en.wikipedia.org/wiki/Magnetic_sail or even this craziness https://en.wikipedia.org/wiki/Bussard_ramjet#Dyson_swarm-based_stellar_engine_(Caplan_thruster)

Probably you’d still want some RCS thrusters for faster reaction times in a pinch. And reaction wheels are “free” in terms of fuel, so there is likely some upper bound to lifetime. But not as bad as normal spacecraft.

Long short: RCS thrusters are probably still useful, but may not necessarily need to be the primary means of station keeping.

not all of our population has adapted to this

“The future is already here – it’s just not evenly distributed.” – William Gibson

Yes, I even once got a B+ in thermodynamics, decades ago. I was proud of that B+ – one of the hardest courses I’ve ever taken.

Yes, AC. It uses energy, adds heat into the total system, and you cannot fight entropy. However, you can mitigate heat gain in other places. You trade local effects for net zero global effects.

Simple example: AC running off of solar. It increases heat by decreasing albedo (solar panels are dark), but if you paint another area white, you can have a neutral effect in terms of total energy captured by the earth. But you can have a net zero heat gain and still have AC.

Obviously you’ll have a harder time balancing this equation if you’re using non-renewable energy sources.

Right – cause rain to fall here, cause a drought elsewhere. Etc. Could probably be weaponised if clever about it.

Sure, it’s just another tarball to compile and install, right? What do you mean lots of dependencies? Oh, well, I guess there is Krita :)

Very cool!

If we’re in string freeze, it’s probably within a few weeks. They’re in bug squashing and translations mode now. I’d take that bet.

More info: https://www.americanartarchives.com/reilly.htm

However, there’s no indication anywhere online that I can find of the location of the original if you wanted to see it. And this appears to be the highest quality version online anywhere.

Engagement, huzzah! Okay, the funding issue is an issue. Ironically, it requires companies like SpaceX (or their competition as they come online) to get the launch prices down. It’s doable though. Back of envelope: The largest solar sail launched so far has been a paltry 14x14m, if my memory serves correctly. In order to reduce the incoming sunlight by 0.1%, you would need something like 60x1000 km of solar sails. Assuming you can make them 1 sq km each, you’re looking at 60k solar sails. But they can be very very lightweight. Wikipedia proposes 0.02 g/m2 as a lower limit… let’s use 0.05 g/m2 so we have some leeway and don’t need exotic materials. Thus a 1km2 solar sail would weigh only 50kg (of sail material). Add another 200kg for some tensile frame and some control electronics and you’re looking at something like a Starlink mass to get 1km2. Sure you’d need 60k of these things, but launching Starlink swarms that size is doable (to LEO – you’d need a bigger rocket than the F9 for L1). Let’s suppose Starship (or similar) is launching them in batches of 60 for $10M/launch… That’s 1000 launches. Currently SpaceX is launching about every three days, so assuming Starship is online and capable, that would be three years of launches at the same rate as Starlink (but with a bigger rocket) and ten billion dollars. Okay, even if costs go up by an order of magnitude, we can do this, now, today, for about the cost of purchasing twitter. Musk really fucked up didn’t he ;)

Okay, that’s a lot of methane to launch the rockets. Back of the envelope, assuming one launch uses ~300t of methane. The per capita use of natural gas (globally) is about 50 cubic feet per person per day. A cubic foot of natural gas is about 35 grams, so the per capita usage in mass is about 1750g/day/person. So a single rocket launch uses about the same amount of natural gas 171,428 people would for one day. It’s actually very small, comparatively. Even if I got my estimates wrong by two orders of magnitude (on total number of launches), it’s still very small compared to the total amount of gas burned globally every day.

Okay, other options: we put the solar sails in a very high earth orbit (above the comms satellites) – doable, but you’ll require many many more of them as they won’t site between the Earth and the Sun during most of their orbit. LEO would cause problems with collisions with comms satellites. You can’t put them very low due to atmospheric drag. Plus, the closer they are, the more likely they are to create where little eclipses as their shadows pass by. L1 really is probably the best option.

Blimps flying around could do it. But you’d need like 60k blimps flying around in the upper atmosphere and each blimp would have to be an engineering marvel to get to that size. Probably not doable.

There’s cloud seeding, as you suggest. But that becomes a political hot potato (blimps would too) due to where the clouds are created. What if China seeded some clouds which cause a torrential rainfall and flooding in Mexico as the atmospheric currents move those clouds. Etc.

A light nuclear winter sounds like a disaster – what do we do, nuke a few volcanoes to set them off prematurely? That doesn’t sound sustainable. Burn all the forests to release ash? Nope, that’s our carbon sink that’s burning…

Ironically, raising our albedo might be a decent local option – just mandate white roofs everywhere. Just under 3% of our surface is urban and white roofs would also help with the urban heat island issue. You can probably paint 0.2% of the surface white. Not as good as blocking sunlight, but useful. The bad part is, solar panels are all dark, and moving to solar decreases our albedo. So maybe this will just offset changes in our average albedo due to solar panels.

Your last option reminds me of: Kill all the poor!

I’m saying you should do your own research

This is the calling card slogan of someone who’s bought into reality rejection…

The educated world is built on a web of trust whereupon subject matter experts must necessarily yield to others when something is outside of their realm of expertise. I am a planetary scientist and geophysicist and spent nearly a decade studying. I am constantly learning things in my own field, and by no means do I have a full grasp on every detail. But I can call out BS when someone talks about orbital mechanics or earthquakes or whatever. I do not, however, know anything about the digestive tract of my cat and yield to the veterinarian who has spent their whole life becoming an expert on these sorts of things. I don’t argue with the vet that I’ve done my own research (watched a few youtube videos) and thus am qualified to disagree with them. Because objectively I know less than them on that subject and no cursory review will solve my ignorance.

When rating the bias of news organizations, what qualifications do you have so that you can do your own research? Do you have fundamental knowledge of the journalistic process? Is the media source covering a topic you are a subject matter expert in? Or are you just lashing out because it doesn’t vibe with your worldview?

The thing about the fediverse is: it doesn’t have to be uniform in how the admins and moderators behave, because federation is an elective process. Don’t like an admin or mod, go somewhere else. Just don’t be surprised when that somewhere else gets defederated.

Almost all non-african countries are projected to shrink or plateau in population by 2100, according to UN estimates. (These estimates cannot account for the unexpected, obviously.)

Image shamelessly stole from: https://www.reddit.com/r/dataisbeautiful/comments/1evz9a7/oc_un_prediction_for_most_populous_countries_eu/

Just need to build a lab in a graveyard then. Checkmate lichens!

Wait until they find they don’t have 2nd amendment rights there

This would be the most circuitous immigration route they could take to get to Europe… go to russia, head to front lines (and survive), surrender, become a POW, claim refugee status (and avoid being deported), land in a western country and start from scratch.

The social media echo chamber has that effect. But statistically speaking, this is humanity’s golden age. The average lifespan is up, we have instant global communication and positioning (wow!), conflict is down (take the wider view)…

Like, even if you added Ukraine and Gaza to this, they’re small compared to historical conflicts. And this graph would be even more pronounced if we normalized it as percentages against the global population – literally the last few generations have been least likely to die in conflict across all of human history.

The global solutions will eventually happen. Right now nationalism gets in the way of it, but on the timescales of geology, nationalism is a blip. Hell, many scholars cite 1648 as the creation of the current system – https://en.wikipedia.org/wiki/Westphalian_system – so hopefully this is just a phase and we’ll get over it and start global scale geoengineering before we get cooked :)

Can you imagine a UN agency in charge of sun shades positioned at Sun-Earth L1 that reduced the total sunlight hitting the earth by 0.1% and halted the heating problem entirely? Wouldn’t solve the carbon dioxide levels, but it’d be a start :D

(The orbital mechanics folks can chime in here. Sunshades at L1 are unstable because L1 is unstable, and sunlight exerts pressure on them like solar sails. However, there are quasi-stable positions slightly sunward of L1 where you can balance these instabilities and actually use the solar sail effect for station keeping in a swarm. It would require launching a lot of rockets, but is entirely doable with today’s technology. Said rockets use hydrocarbons to launch, ironically.)

My gf calls me a “radical optimist” for believing in people eventually doing the right thing :)

Scientist piping in with my two cents. Granted my speciality is geophysics and planetary science, and not specifically climate.

In geoscience we tend to talk about things on very long timescales. Like: at what point with the sun’s output cause the earth to turn into Venus (250 million years as a lower bound, ish, then all life is doomed on Earth). The rate of change we’ve applied to our atmosphere is faster than any natural process other than a meteor strike or similar event. There are climate change scenarios where all life on the planet dies (why wait 250 million years!?), but they’re mostly improbable unless we have some sort of runaway feedback mechanism we’ve not accounted for. 2/3 of humans dying is also unlikely. Coastline and ecosystem disruption are almost certain though.

The thing about humans are: we are frighteningly clever. We can build spacecraft that can survive the harsh environment in space and people survive there. As long as climate change doesn’t happen “too fast” (values of “too fast” may vary), we will engineer our way around it. On the small scale: air conditioning; and on the larger scale, geo-engineering (after accumulating sufficient political will). We’re so clever that, if we (or our descendants or similar) can probably even save the earth in 250 million years when the sun’s output passes the threshold where it wants to fry us – assuming we survive that long.

That doesn’t detract from her statement. But it is the Mirror, and the headlight is trying to be incendiary.