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Comment by gl-prod | Hacker News Reader

"It would make no sense to plan on building and replenishing ever larger space sunshades to counter continuing and increasing use of fossil fuel. The same massive level of technology innovation and financial investment needed for the sunshade could, if also applied to renewable energy, surely yield better and permanent solutions." - Roger Angel

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One needs it only long enough to tide us (humanity) over till we have viable alternative shoe-in solutions.

Without that, turning on a dime away from hydrocarbons toward renewables only will inflict lots of damage to progress and people in both rich and poor countries as well.

We need an intermediate solution to attenuate the impact of hydrocarbons while we transition to alternative energy sources gracefully.

Lots people who advocate for the "bandage tear-off" fix are those who envision being able to withstand the consequences of such a choice. (Oh, I'll telecommute, I'll take the train, I'll get geothermal, I'll move to a mild climate, etc.) Most people don't have the above choices.

Easier from a perspective of organization and governance, too. Energy policy can be managed with existing institutions. If you want to launch a megafleet to block the sun, who they hell do you ask for approval? The UN? How many countries do you need to sign off on it?

If the "you" here is not the all powerful US, it's a certainty that there will be a war over the project.

If it's the US, it will "just" lose a lot of soft-power.

What if it's not even the US but some private company with launch capabilities that also may or may not be US based?

Friendly reminder that a private company with launch capability currently is massively increasing the space junk problem and about to trigger the Kessler scenario for a quick buck and internet access without cables, while at the same time ruining surface-based astronomy.

So why stop there? And as always, the Simpsons have predicted it: https://www.youtube.com/watch?v=L3LbxDZRgA4

I'm no Musk fan but is this true? I thought Starlink was low altitude so everything would fall back down pretty quickly. And while I imagine its not great for astronomy surely it's not much work for some institution or enterprising individual to create a tool for using the known position and timing of such satellites to help remove their impact on images?

Low-altitute, quick-decay orbits are fine as long as the satellite does not get damaged. Once one satellite is hit by something, the debris field will spread to all kinds of orbits, some of them pretty long-lived. [1] is a fascinating read that describes the phenomena surrounding orbital crashes.

[1] https://www.universetoday.com/103650/space-debris-a-tale-of-...

Well, just to keep in mind, internet access without cables is very valuable, and possibly the most valuable use of that space we can have.

It's important to control the space junk problem, of course. But not at the cost of not using the space.

The US will use 20 million barrels of oil today, just like yesterday. Who had to sign off on that?

That won't be necessary as fossil fuel is limited anyway. We're already past peak oil. Eventually we will have burned it all.

But I agree it's a technological bridge too far. I could see it help to fix the damage already done (and the damage to be done before we can move to fully renewable) but I don't think it's realistic.

But I don't think other mitigation methods like carbon capture are realistic either (not at a scale to actually matter).

Peak oil is/was a myth. There is at least an order of magnitude more oil than we could ever burn without causing a runaway greenhouse effect.

Peak oil as a concept only ever made sense if you assumed a static price of oil. There are immense reserves when the price per barrel rises, or when new technology like fracking opens up new reserves.

That's true. Except the little detail of time. We've already passed the time when that rational and sane option was viable. Now we're in a situation where we need both.

This also puts all of our eggs in one basket. That would seem to be a troublesome thing to do.

This is a terrible take. First of all, the price of space launch is plummeting, making the cost of launching a fleet of sun shades drop like a rock. It may soon be veeery affordable. Like, something Elon would do just for the kicks.

Second, there are distinct advantages to higher CO2 levels in the atmosphere. It makes agriculture grow more quickly, leading to higher food yields. And the greenhouse effect is mostly independent of latitude so places like Siberia and northern Canada become habitable while the tropics do not become so hot as to be unlivable. Raising the global temp by 2 degrees could double the amount of high quality arable land suitable for dense human habitation.

Third, instead of a sunshade we could use a larger translucent film which blocks UV-B light like sunglasses. Imagine a world without skin cancer!

I'm not an expert but blocking UV-B may have some negative consequences.

It does not. UV-B is ionizing radiation and is incapable of being used by biological processes as a source of energy. About the only effect it has on our biome is that it contributes to the production of ozone, and it is possible that filtering out UV-B might reduce (but not eliminate) the ozone layer. However the main/only benefit of the ozone layer is to filter out UV radiation, so...

UV-B is like mosquitos, one of those rare things that really only does cause harm and can be safely eliminated if possible.

Imagine a world where bees can't see the centers of flowers.

Bees see with UV-A light, not UV-B.

Bees see with both. UV-A (320-350nm) and UV-B (290-320nm) both overlap with bee visual spectrum (300-650nm).

Do you have data on which flowers in which geographical areas reflect with UV-A and/or UV-B? Maybe to bolster your argument you will need to prove that this won't affect bees, and pollinators more generally.

The harmful UV-B rays are under 300nm, and that’s the cutoff for bee vision for the same basic biological reason. Below that limit is what you’d want to filter out.

Imagine a world without skin cancer by launching giant space sails is like saying: imagine a world without white people.

People have evolutionarily adapted to the sun by producing melanin in their skin, but for some reason aerospace is the only answer?

Why the West (and frankly many on HN) seems so content on destroying the natural world for problems that only matter to a subset of rich people somehow still surprises and amazes me.

There are distinct advantages to making the internet unlivable, so that insane comments like this don’t have to exist anymore.

>There are distinct advantages to making the internet unlivable, so that insane comments like this don’t have to exist anymore.

I always imagine these kinds of things starting in a conversation of a bunch of stoners munching on Funyuns while chugging Mountain Dew. "Like, dude, it would be so cool, if like, we made a giant sun shade in space. That'd be so rad!" Only someone thought it sounded smart when heard from outside the circle which is the really sad part.

At least one of us has worked in the aerospace field and has relevant domain knowledge to evaluate the feasibility of this idea. I'm gonna guess its not you.

Well that's just kind of dumb logic really, as if it were you, you wouldn't need to guess it was me now would you. Sometimes, smart people can be kind of not smart.

Also, at least one of us can get a joke, and I'm guessing it's not you

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