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Comment by kamranjon | Hacker News Reader

I am so much more interested in Venus than Mars. They say the upper atmosphere is much more habitable than the surface of Mars. The density is apparently perfect for floating cities. I wonder why there is not more focus on it.

Edit: here are some interesting links, a NASA concept manned mission that revolves around the floating concept: https://en.m.wikipedia.org/wiki/High_Altitude_Venus_Operatio...

And some general info about colonizing venus, the advantages section outlines some of the reasons I'm excited about the idea: https://en.m.wikipedia.org/wiki/Colonization_of_Venus

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People on HN start this discussion whenever there’re any news about Venus/Mars. But at this point I don’t even care which planet we colonize first. As a layman, I think it’s an engineering problem and all we need is money. Let’s just go SOMEWHERE.

Someone usually says: “Yeah but what about curing cancer first?!” Guys, the war on cancer(or HIV/Alzheimer’s/whatever) has been going on for decades. We can’t wait forever, as there’s always going to be next disease to take care of.

“And what about eradicating poverty on Earth first?!” Just hear me out... imagine how many people we can put to work(with decent wage!) if we put enough money on the interplanetary flights? We’d invest in science, engineering, production... Well, I’ll keep dreaming.

Seems like a potentially great way to transfer a lot of wealth from taxpayers to the aerospace industry for a very long time with little oversight or roi.

In ideal world, we'd transfer wealth from football players, singers, actors, traders etc.

Or maybe we give more thought to the feasibility of space colonization and give people the ability to opt out of paying for this kind of adventurism?

I work really hard and would rather my taxes go to helping out those living today, not maybe those living in 1,000 years.

I agree with you. It's driven by nothing more than sci-fi fantasy. Robots are the future of space travel and public funded inventions for those do end up bringing useful technological advances in the future.

Is that not what has been going on with the possibly questionable cost-plus approach of NASA, let alone the US Military contracts and similar government grants for feasibleness research without commitment?

Also, if we cure all the diseases, where are we going to put all the people on this already over-taxed air bubble?

>Let’s just go SOMEWHERE.

Why though? We have robots exploring other planets and comets/asteroids and stuff, still sending data from beyond the solar system. We are places. What do we even get out of it that robots on other planets wouldn't be able to accomplish? If there was a new task humans would do, you could likely just form a way for a robot to do that task.

I'm no expert, but it seems that the tasks robots can do are rather limited. Especially considering that they're remotely controlled, there's a huge delay between command and action.

If we had humanoid robots that match us in agility and intelligence...Well, that'd be a completely different story.

I'm no expert, but one thing which concerns me about Venus is the feasibility of sourcing local materials. It would be way more expensive to fetch resources from the surface and carry them up to floating cities, even in the energy cost alone, not accounting for the hellish conditions the equipment must endure - for thousands of duty cycles.

On Mars, the regolith is right there. You can just scoop it up and use it. Much easier to turn into buildings, extract resources from it, and so on.

I think we can colonize Venus, and ultimately should, but it presents a lot more problems than Mars. Mars makes a lot of sense as a first step.

why not try the moon first, before mars?

We should definitely do both, and we'll almost certainly have people on the Moon again before sending them to Mars, if for no other reason than to test some of the necessary technology. I hope that a permanent human presence on the Moon becomes a reality soon.

But there are lots of reasons to go to Mars, too. For one, it's much harder, which means a lot more innovation will be required to get there and set up a colony. Unlike Venus, though, these are one-time costs - the long-term economics of Mars are likely to be more sustainable. Mars is also richer in natural resources, not the least of which is gravity - we're not sure how much gravity humans need, but we do know that spending a lot of time in zero G is bad for our health. The Moon's gravity may not be sufficient for long-term individual habitation, or for rearing children. Mars also has an atmosphere, from which we can source useful gasses, and which provides (some) protection from radiation, and which gives it weather, making it a more dynamic and interesting place.

In any case, if we can colonize Mars, the same technology is applicable to the Moon, and we'll almost certainly apply it as such around the same time.

I've always had a soft spot for Venus. The floating city idea is not my favourite, perhaps for research there could be applications. A monumental breakthrough in carbon sequestration, in method and cost might do it for Venus though. But I mean monumental. Back of the envelope calculations say there's about 460 Quadrillion metric tonne of CO2. Sooo, maybe at a cost 1c per metric tonne we could get it done with a current day cost of 4.6 Quadrillion US Dollars or so. Or all the worlds GDP for about 50 years. But that assumes that there would be no benefits from doing that. Could be other applications from the byproducts being sold.

it's always seemed to me that the serious problem with Venus is it's rotation speed. if it wasn't so slow I think you could turn it into a legitimately nice planet very long term. Mars on the other hand lacks the necessary macros, it's likely always going to be a rough place to live.

Yeah it is remarkable that cloud cities on Venus are very quickly dismissed but terraforming a dead rock is...uh feasible?

How would you build a cloud city?

Also, given they would be floating above hell, why would you?

Mars' ground will not burn you to death, but the occasional solar flare due to missing magetosphere might, or the cosmic radiation, or the toxic soil.

That hell happens to be rich with all sorts of industrially useful chemicals. Seems like a decent reason to me.

Seriously? Start with your standard orbital space station. Add a bit more structural support and stiffening, then lower it into the atmosphere and use balloons to keep it at a set altitude. Voila, cloud village. Repeat as needed until your village is a city.

Seriously? That isn’t how orbit works at all. With that plan you just reentered the whole thing, broke it into a million pieces, and rained it across the surface in a triumphant meteor shower of flame. Voila, everyone’s dead. Unless you had a plan for managing the atmospheric friction from orbital velocity that I didn’t read.

In orbit things move sideways with respect to the surface. Fast. So the only way that works is if your “standard orbital space station” has enough propulsion to deorbit itself and hover in place — now that orbit is no longer cancelling gravity — until cubic kilometers of balloons that need to inflate (with what?) could hold it up. That amount of dV is barely theoretical at this point and would require several technological breakthroughs. You’re basically proposing deorbiting ISS without the atmospheric reentry and fiery death part, and given the similarities between our planets and their atmospheres it’s not a poor comparison.

Could you please stop creating accounts for every few comments you post? We ban accounts that do that. This is in the site guidelines: https://news.ycombinator.com/newsguidelines.html.

You needn't use your real name, of course, but for HN to be a community, users need some identity for other users to relate to. Otherwise we may as well have no usernames and no community, and that would be a different kind of forum. https://hn.algolia.com/?sort=byDate&dateRange=all&type=comme...

First of all: Send some probes, explore, test.

See Cloud Nine https://en.wikipedia.org/wiki/Cloud_Nine_(tensegrity_sphere)

I have a very hard time buying the idea that cloud cities are a more achievable idea.

Every technological achievement seemed laughable before its time. Sure a "faster horse" was more understandable, but cars were actually more feasible.

Not "every technological achievement seemed laughable before its time". Some were even imagined long before they came to reality.

Also that does not make every idea imaginable also achievable.

And conversely a lot of technological predictions were considered pretty seriously which are pretty far away from today (look at all the future predictions of the early 20th century. Flying cars and humanoid robots and all).

Your comparison with existing cars replacing horses at that time is pretty out of whack with our abilities right now and the task of terraforming Mars, even the question IF making it habitable is even possible. We cannot even redirect asteroids...

Sure, I was being a bit flip with that response. But I think the point I was making stands. There are certainly innovations that sounds illogical but turn out to be very successful. Just because something sounds like a bad idea doesn't mean it is, it just means it hasn't worked yet.

I actually don't think cloud cities sound that ridiculous either. Just like I also didn't think landing a rocket on its tail ever sounded unfeasible.

> But I think the point I was making stands. There are certainly innovations that sounds illogical but turn out to be very successful. Just because something sounds like a bad idea doesn't mean it is, it just means it hasn't worked yet.

No because your point was about horses being replaced by cars, which is what people (and probably horses) were skeptical about at that time. In the same way IBM was saying that computers will never appear in homes, etc.

But these devices were already there. The misconceptions were about predicting demand and miniaturization. This is completely different from terraforming. You are comparing "oh these devices sure never will be popular enough to make this other thing obsolete" with "lets nuke the Mars to create an atmosphere so we can live on it" (always winter, yeay).[0]

Your argument is bad because by saying "technologies were laughed at in the past" every technology that sounds laughable should be taken seriously? No. This is the same trap that Theranos investors had fallen in. It is all a fantasy.

We humans are very bad at estimating what is possible and what not. E.g. our inability to divert asteroids [1]. That is already a hard problem and currently not possible to do.

I am not against crazy technological ideas, for example the space elevator had a surprisingly good feasibility to being realized before we polluted our planet's atmosphere with junk. Terraforming Mars is in the Theranos land of crazy ideas though.

> Just like I also didn't think landing a rocket on its tail ever sounded unfeasible.

Maybe because that was already demonstrated in the 90s [1].

[0]: https://www.space.com/elon-musk-nuke-mars-terraforming.html [1]: https://www.youtube.com/watch?v=4Wrc4fHSCpw [2]: https://www.youtube.com/watch?v=wv9n9Casp1o

Not sure how you got off track, but my point was that building cloud cities on Venus seems no more unrealistic than terraforming Mars. Both are really fucking hard, but Mars probably sounds easier to the poster I was replying to because it is more similar to what we've seen in the past.

At least the cloud people would be able to see the Sun at the sky (and, for comparison, meteor people would be able to see it under the floor). I dread to imagine what a Mars colony would look like.

We have decades of steampunk literature to learn from :D

Cloud cities are kept aloft by flimsy deals with sith lords. It's just physics.

Because building a cloud city isn't not end of the problem (and not a small one in itself). Sustaining a cloud city is very difficult. Terraforming Mars is being considered for the fact that it could be a near permanent solution.

"permanent" how? The fact that it has ended up a dead rock implies that that's its steady state. You make mars habitable, it'll probably require a perpetual gardening effort to keep it that way.

It would be effectively permanent. The sun would strip the atmosphere over a period of time on the order of a hundred million years. If we could terraform it in the first place maintaining it would be trivial.

https://astrobiology.nasa.gov/news/how-to-give-mars-an-atmos....

I've talked with Dr. Green about the parasol idea, we still need to do a stability analysis since L1 is unstable, how much effort will it take to keep the dipole in place given the solar wind can fluctuate by an order of magnitude in either direction of the average. It's a fun problem.

I wonder if having an adjustable center of mass would solve this problem.

A mass ejection method would have to be maintained too often, but CoM adjustments can largely be automated (at least in principle).

The simulation I want to do involves manipulating the dipole strength, since it's deflecting solar wind, there's momentum exchange, if you fluctuate how much area you're blocking out you could get more or less drag as necessary.

If you're going to Mars you may as well live underground to avoid the asteroids, dust and radiation.

What if Venus already has sentient life? Either pre technosignatures or too sophisticated to advertise their presence to the tribe of nuclear monkeys across the pond.

We can't just go waltzing in there and "terraform" something that isn't ours. We'd had to work it out first with whoever's there.

On the cloud city sustenance point isn't there ample mining to be had? Like Lando

There’s nothing to mine. The atmosphere is mostly carbon dioxide with a little nitrogen. Everything else is in insufficient quantities to make it worthwhile probably ever.

Cloud City worked because they mined a magical gas called tibanna that generated no magnetic field, no radiation, was denser than air, and dissipated heat so well there was no turbulence.

The idea is intriguing, but floating cities makes me think there’s little tolerance for error (or a very easily reachable point of no return).

The platform itself has to be constantly maintained, which requires a crew. Military or at least cruise ship with disciplined crewman, rather than anything civilians can be trusted or expected to maintain.

Maybe the expectations of a "cloud city" should also be lowered. I guess it would be more like the ISS and less like Lando's station.

The general idea of colonization of other planets is in general much farther away than your average tech billionaire wants us to think :)

I think you can design in error tolerance, with a bit of imagination. Imagine a flotilla of connected balloons, instead of one giant balloon; build in enough tolerance that a sagging balloon is supported by its neighbors until it can be fixed up.

Ultimately, it's a question of building a floating thing, and keeping it floating. This strikes me as not-too-hard, compared to the usual space problem of trying to hold oxygen in a bubble in a vacuum. You just need a sustainable way to 'recharge' the balloons; that really just means filtering lighter gasses from the air and pumping them in faster than they leak out. The Venus atmosphere is primarily CO2 with a bit of nitrogen; the game is then filtering out CO2 and filling the balloons with nitrogen. Coincidentally, we have people putting lots of thought into efficiently filtering CO2 from air already...

Does it need to float? Could not some sort of mountain plateau work that's the right altitude but perfectly solid ground, just high in the sky?

The safe height is on the order of 50 to 60 kilometers up, so that’s a tall order.

Grade school me always thought it was actually pretty simple. More heat means more energy. Just because we don't know how to harness it yet doesn't mean we can't. We live off of the sun. Why would were go farther away instead of closer?

Maybe naive thoughts, but are they wrong?

You need a heat gradient to take advantage of it. An uniformly hot place like Venus is a hard thermodynamic place.

Mercury and our moon are actually interesting in that regard. I had similar fantasies as a kid, a huge pipe with a thermal fluid taking advantage of the difference in temperature between the cool and warm side of the planet/moon.

But with today’s prices on solar panels, this will probably never happen.

gravity on venus is more similar to earth than mars, too

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