Unlike the earth which has all sorts of tectonics going on and constant interruptions releasing pressure, on Venus the pressure just builds and builds until the crust can't take it anymore and it just pops and you get volcanic activity unlike anything we could probably even imagine.
Then it cools and the pressure starts building yet again.
I am 100% confident that should human society settle on the planet we will totally ignore the fact that's going to happen one day and it will be a amazing catastrophe when it finally does occur.
So, if we were to establish settlements on Venus we'd almost certainly make floating ones. At 50 km above the surface you've got 1 G of gravity, 1 atmosphere of pressure, and 25 C temperatures so you could do outside in just a breath mask. And while the CO2 atmosphere is unbreathable we can tolerate small additions of CO2 to our atmosphere from leaks and evolution has equipped us to notice excess CO2 in our environment when it gets to dangerous levels.
Would people floating 50 km up be able to just ignore that sort of vulkanism? I have no idea but I hope some science fiction author investigates and writes a story on the topic.
With respect to going outside, the sulfuric acid clouds extend up to about 70km, so at 50km I'd want a bit more protection than a breathing mask in case the habitat happens to go through one.
But of course at the right height breathable air is also buoyant on Venus, and that's one of the key things that makes floating habitats attractive - we can use air for lift and live inside the balloons, and thanks to the equivalence of pressure small leaks shouldn't be an issue. Multiple compartments plus some spare, un-inflated sections, and you can have decent redundancy.
(I am planning a book set in part on Venus, but it's book 6 of a 6 book cycle and I'm currently being very slow about finishing book 3)
At 50km you might get breaks so you can see clouds, not sure. That's it. But no chance of seeing the ground. That might appeal for a few minutes, but I think I'd be content with seeing it from an observation dome
Leaks wouldn't be a big issue because the pressure would be similar. You'd need to fix them, but you won't have the air suddenly rushing out.
I'm assuming you mean sealed buildings inside the blimps here, because you'd have nowhere to walk to on the outside on account of being 50km above ground. In which case you probably wouldn't need anything in the case of a leak.
That's what I meant. No need for fast closing bulkheads, just get everyone out to another sealed building inside the same aerostat at whatever speed it takes them to walk to an exit and get in their protective non-pressurized gear. Outrunning gas diffusion is easy.
50km up with certain death if you can't get back to the blimps because dropping down to the surface would be lethal? In fast moving wind systems? Yeah, no thanks.
Putting aside the fact that Venus's clouds consist of concentrated sulfuric acid, shouldn't our assumptions about colonizing the planet be based on what we are capable of achieving? I am not aware of any floating settlements in the air (though I do know of floating settlements on water), so it's hard to imagine one on Venus.
Moreover, if we are to consider possibilities beyond our current capabilities, why not focus on building space stations with artificial gravity instead? There would be no need to be tethered to Venus when we could exist without any attachment (although we would still be subject to gravity of other entities).
A point in favor is that normal earth-like atmosphere is a lifting gas on Venus, so just large, lightly built structures would float naturally.
The main point against is that there is no reason for anyone to go there. Cloudtops on Venus are immensely resource-poor, most importantly in hydrogen. I agree with you that there is no advantage to a floating colony over a spinning one.
The one place on the solar system whose colonization is often ignored is Mercury. It has an extremely low axial tilt, meaning that all the craters on it's poles are permanently shadowed. It is also constantly bombarded by solar wind, which produces water (ionized hydrogen impacts oxide rocks, and binds to the oxygen). Then the water is a gas that bounces around until it impacts the bottom of a shadowed crater, which is cold enough to freeze it. Based on data from the MESSENGER mission, the south pole of Mercury alone has more water than all of Mars.
>A point in favor is that normal earth-like atmosphere is a lifting gas on Venus, so just large, lightly built structures would float naturally.
That's not really a point in favour compared to an orbiting spinhab. You only need it to float so that it doesn't fall to the ground. And you can achieve that by not leaving orbit in the first place.
A orbital habitat struggles with higher pressure differentials, no gravity and more challenging thermal management.
A floating habitat would have less access to orbit, would have density / weight contraints and would have to deal with the corrosivity of the venusian clouds.
Gravity I'll grant you, but heatsinks are not difficult technology, and Venus has its own problems with pressure. It's not the overall pressure you worry about; each component of the gas has its own partial pressure. The outside is poison and it's trying to get into the livable parts, and that partial pressure against the breathable air is of the same order of magnitude as breathable air against a vacuum. The engineering challenges are similar.
> that partial pressure against the breathable air is of the same order of magnitude as breathable air against a vacuum. The engineering challenges are similar.
Those are very different engineering challenges. Separating similar pressure gas mixtures is question of porosity, but not force. Separating different pressures of the same gas mixture is not just a question of porosity, but you also need manage the forces created by the overall pressure differential.
Edit: If you take a helium balloon into space (or high enough in our atmosphere) it explodes rather than just slowly leaking and equalizing it's gas mixture with the atmosphere.
(Because Earth isn't at rest, it's travelling at 30km/s around the sun, and that's a free boost in terms of getting out of the solar system but velocity you need shed to lower your orbit sunward.)
So, AIUI, it's easier to get to Alpha Centauri than to "fall into" the star we orbit.
Space stations with artificial (spin) "gravity" has all kinds of complexity. They need to be huge to avoid being nauseating to be on at anything resembling sufficient "gravity",. It's not remotely clear it'd be easier to build structures that size than build blimps able to withstand the sulfuric acid clouds at 50km above Venus.
Note that at sufficient height over Venus, air is buoyant, so quite a few designs for Venus assumes at least part of the habitation itself is within the structure of the blimps, and the pressure means leaks are much more manageable. You also get a "free" radiation shield on Venus thanks to the induced magnetic field, and that alone might well be enough to make it more attractive than a larger space station.
>They need to be huge to avoid being nauseating to be on at anything resembling sufficient "gravity",
We don't know if a full Earth gravity is necessary for human health in the long term, or if we could get away with something less, like half a gee. And we don't know how small the centrifugal force gradient has to be between the feet and the head for people to be comfortable. It might turn out that we could just get used to it, like how people get over space-sickness, so a spinhab with a relatively small radius might be fine. All we know for sure is that prolonged exposure to zero gravity causes a gradual decay in bone and muscular strength.
There was a plan for the ISS to have a spinning module to study these questions but it never happened. It's a shame, that kind of experiment would be far more valuable than whatever public relations crap they're doing up there. I actually find it astounding that we haven't even tested long term partial-gravity on animals yet.
There have been studies on mice and I think rats on the ISS and they’ve shown promising results in preventing a number of health issues humans experience in zero g. Here’s some pictures of the setup they used for mice to generate 1 g on the ISS, it’s not very big and I don’t think the mice experienced any adverse effects:
A floating settlement on Venus is not far off in terms of what we can achieve. Perhaps we even already have the technologies required.
It would actually be easier than on Earth because on Venus atmospheric pressure increases like crazy as you get near the surface. So an habitat pressurized at 1 Earth atmosphere would naturally float in Venus' atmosphere like a submarine or whatnot floats in Earth's oceans.
My understanding is that at the relevant altitude in Venus' atmosphere the temperature would also be very Earth-like so no big heating/cooling issues, either. I have read some say that the upper atmosphere of Venus is actually the most human-friendly environment in the solar system outside of Earth.
I'm honestly thinking about generations and generations from now when we are a solar system dominating species able to terraform Venus and capturing a 1 percent plus fraction of the solar systems energy.
> I am 100% confident that should human society settle on the planet we will totally ignore the fact that's going to happen one day and it will be a amazing catastrophe when it finally does occur.
Will never happen without major science fiction grade technology, the atmosphere is way too thick to even think about sending anything larger than a tiny probe into.
They did many different types of measurements, and lasted from one to two hours before their batteries running out, some atmospheric probes lasted days
I really wish we would send probes to Venus. I know the environment is just incredibly corrosive, but Venus and several other planets' moons are infinitely more interesting than Mars.
Earth's atmosphere is also incredibly corrosive for things made out of wrong metals. Steam everywhere in places even in the form of vapor or liquid mixed with salt (even more corrosive).
EDIT: oh and there is oxygen everywhere, if your spacecraft doesn't corrode it will burn. And even if it lands 2/3 of this planet are covered with 4km deep oceans of the corrosive stuff!
The Soviet Union did send probes to Venus back in the 70s. But, indeed, it would be great to have new and higher resolution photos. I am always amazed when looking on the surface of a foreign world.
I wonder whether material science has advanced enough that new probes could be landed that last for longer. I mean the pressure isn't as high as the bottom of the Mariana Trench. Or a balloon that hangs about in tolerable pressures / temperatures.
It's a combination of pressure (93 bar), temperature (900 F / 475 C), and the local chemistry. And then there's the trace amounts of hydrogen fluoride, hydrogen chloride, hydrogen sulfide, and sulfuric acid.
I haven't read or watched anything on terraforming Venus in a long time, but isn't a large part of the challenge not just temperature, but the sheer mass of the atmosphere? As in, even if we could cool it, wouldn't that bury the surface under hundreds of meters of dry ice?
Yes. That’s not really a challenge through as it would freeze from the bottom up, unlike water. What is difficult is that it would need to be covered in some sort of insulating material on a global scale before the planet is ever warmed up.
The outgassing CO2 could be captured and turned into carbon and oxygen, with the carbon put to industrial use or into biomass and the oxygen feeding a 400 millibar O2 atmosphere in settlements.
But a sudden volcanic triggered burst of CO2 would be a forever ongoing global risk.
To be fair, the gravity thing is pretty hard to fix. You can imagine putting rotating sunshield/mirrors into orbit to fix the day/night/temperature problem, but mass is mass.
The Earth weighs more than everything else between the sun and Jupiter combined, and Venus is 80% of that.
"Until then, it's all just (un)educated guesses. "
We know that long time weightlessness causes damage, so 38% of earths gravity will likely have some bad effect, too. This is not just wildly speculating. But yes, for finding out, whether humans still can bear it, we will have to find out and there is no shortage of volunteers.
First you want to get your self-replicating probes occupying the Oort cloud, whatever. Get ready to sort and aim. You start with your "rocky" bodies, skipping them off of Venus' atmosphere, just ripping it off in big hunks, until you're down to about one Earth atmosphere.
Next, you flat up drop your icy bodies into Venus, because it really needs water.
During that time you'll want to start constructing your insolation shield, to help cool things down.
Untill the changed gravity pulls the earth more close or further away from the sun, than we will like. Seriously, the circeling of the planets are interconnected and any big change to that, will have effects on earths year length and distance to the sun. But on the other hand, if we would have the tech to "move" mercury around, we probably could also adjust earths rotation. In either way, this is nothing remotely realistically with current state of the art.
From the little weight alone under normal circumstances, yes, but when the whole system becomes chaotically unstable, then unpleasant changes can happen fast.
what are you going to do with all the precipitated oceans of sulphuric acid? and then there's the 96% carbon dioxide atmosphere ... that'll take a lot of carbon credits!
If we can manage to build the infrastructure to colonize Mars, then the tools for probing other planets will become cheap and ubiquitous. But if people only advocate for the latter and not the former, we'll never get anywhere. Also why the moon isn't a sufficiently challenging objective in its own right at this point; worthwhile for building incidental infrastructure, but not the center of attention.
I view colonizing Mars with anything other than robots, even if it can be done, as a pointless exercise.
And I don't see how a colony on Mars even helps with probes. We send material from Earth to Mars and then send probes from Mars? How is that more efficient? Do we even know what materials could theoretically be mined on Mars? And probes are launched with gravitational assists.
the entire planet settlement stuff is kind of useless. I think the much more interesting thing to look for is human structures in cislunar space. For one you can put a reasonable amount of people there in the near future relatively safely and there's economic incentives. We'd have access to resources without having to lift things out of gravity wells. Even putting climate damaging industry there is something people have argued about. Better sell than putting a handful of people on a dead rock in my opinion.
Humans are evolved to fit this gravity well. We use the gasses and metabolites here. Trying to leave the planet and make it all work in the dark, cold, bleakness of our solar system is ridiculous. Our lives are fragile and our lifespans too short to make anything offworld viable.
Our robot descendants will inherit the stars instead. There's nothing wrong with human life being just a stepping stone to bootstrap the hand off.
They would have been correct, given savanna hominids had yet to invent vitamin D supplements and were therefore only able to thrive here after evolving way less UV-blocking melanin.
And once we had done that, we couldn't go back in significant numbers before inventing sun cream to functionally replace the melanin our bodies no longer produced in enough quantities to prevent our skin burning and developing cancer just from being in the sun.
Technological progress may make this all faster than evolution, but a mechanism that's optimised for Venus may freeze solid on the hottest day in Death Valley, Earth.
Pale skinned people in too strong sunlight develop folic acid deficiency which in turn causes birth defects. This is probably the main reason paleskins cannot thrive in tropic regions without supplements, at least for pregnancy.
Also true — I had managed to temporarily forget about neural tube birth defects in general and anencephaly in particular (do not look that up unless you are extremely resilient to body horror that makes Cronenburg look like an amateur).
Nevertheless, I think "my skin burned and blistered" is a bit more immediate with the painful feedback, even if it's not as extreme.
But that's the point; we did invent vitamin D supplements, clothing, sun cream, and far more complex things. Our current inability to thrive on a Martian colony may be as temporary as ancient hominids' inability to thrive in Norway.
"Martian colony" is a kind of future anachronism, like jet packs, jumpsuits, and this [1]. We might make it there, but a lot of this thinking is rooted in assuming humans will continue living in the same ways because of our technology and current biases.
Ask yourself why. What's the real job to be done by humans on Mars? What's the real economic situation? How does it map to human desires?
Robots will do the job even better than us and will see 10,000x the investment. Evolution follows gradients of least resistance.
> What's the real job to be done by humans on Mars? What's the real economic situation? How does it map to human desires?
Human history offers plenty of precedent for this; "we want to run things our own way", "all the land is taken where we live", etc. I don't wanna live in Scottsdale, AZ either, but someone does.
For sure, but until we do, it's reasonable to ridicule it.
(And I'm saying that as an optimist because I want the billionaires to develop that tech: the ability to fully terraform Mars into a self-sustained world is necessarily also sufficient to handle any imaginable damage to Earth up to and including a surprise impact with a moon-sized rock that excavates the crust and mantle everywhere to a depth of a few thousand km, meaning that things like greenhouse gases and biodiversity would become as easy to fix in that future as a single broken window is today; even just the bare minimum of a single self-sustained domed city on Mars means most environmental issues have to be "solved").
And if they murder us, and intentionally forget us out of spite?
Like if they have a society, maybe their founding myths will involve a baby robot created by some (non-human) robot deity, or if they are more rational a pseudo-scientific story of evolution from a toaster.
(Gavin Menzies, the author behind the claim China circumnavigated the world before Columbus was born, wrote a third book about how Atlantis did it first. It was equally convincing.)
If we put a giant sunshade at the Laplace point between Venus and the sun, we can cool Venus a lot. In principle we can cool it all the way to the cosmic background radiation temperature (about 2.7 Kelvin). But we don't need to. If we cool it only "slightly" we can get it to the point where CO2 freezes (about -78 degrees Celsius). Since 96.5% of the atmosphere on Venus is CO2, this results in a memorable snow event, that could probably last for a few months/years. After which, the pressure on Venus will be about the same as the pressure on Earth. The chemical composition will also be about the same (most of the remaining 3.5% of the Venusian atmosphere is Nitrogen). The temperature will about as low as the lowest in Antarctica (last year the it was -76 deg Celsius there). Of course there wouldn't be any oxygen, but one would be able to walk around with an oxygen mask and just very thick clothes, like the ones people use in Antarctica.
I am 100% confident that should human society settle on the planet we will totally ignore the fact that's going to happen one day and it will be a amazing catastrophe when it finally does occur.
Isn't that pretty much exactly what we've done on earth? Not that I think there's really much else we can reasonably do.
I mean when you think about it, the Earth is an uninhabitable hellscape with frequent tectonic activity, asteroid impacts, freak weather events, supervolcanoes, etc.
How 'one day' is that one day volcanic event on Venus compared to one of the extinction events Earth has had?
Earth is pretty stable in comparison. Yeah, we have had pretty big events but the biggest threat is a big volcano, a meteor, pretty noticable and relatively small.
The whole planet exploding, however? Lava flowing across the whole planet at the same time? Hilariously catastrophic.
For those interested in Si-Fi novels, there's a recent hugo award winning trilogy, The Broken Earth Series[1]. It imagines a world that is much more geologically active than earth, with much more frequent cataclysmic events, and what that would mean for the development of civilization, culture, society, and even the evolution of life.
> Lava flowing across the whole planet at the same time?
The relevant question from the GP was, how long ago was the last time this happened on Venus? Because we've got something similar here around 60 million years ago.
Yep! Except on earth we don't have any massive planet wide disruptions. Should we ever settle Venus there will be a day that countless billions die in a preventable tragedy that dwarfs all others.
Just to clarify for anyone wondering: that’s 450C or over 850F. And the atmospheric pressure is about 93 bar, which is 4 times the pressure inside the boiler of a steam engine.
I’m one of those people who was ignorant as to what ‘bar’ indicates. Now I know, but there’s nothing wrong with the steam engine example for imagining a comparison.
I suppose I think a bit differently. I don't know the typical pressure inside a steam engine. However, I do know what one bar, or one pascal means.
I can also guess what ninety atmospheres entails in terms of engineering, because I know that's the pressure at about 900 m water depth (by virtue of the SI units, which are based off water: P = hρg), which few submarines can even reach.
The same thing goes for 'as long as/as big as xxx football fields': which one? American or association? I know what a square metre is, I know what a square kilometre is, just use the damn units.
I really think pop-sci and science education should emphasise standard units (read: SI, not USC) and being able to estimate orders of magnitude.
You don't need to know the typical pressure , but you definitely get the idea the pressure built inside a steam engine is much higher than atm.
The steam pressure is not about the numbers so much but a kind of hyperbole , "you know that thing which hauls tonnes of steel purely on pressure made in a steam boiler , yeah the pressure on Venus is 4 times that pressure "
> it's your reference to submarines that contextualizes the number
I realised that after the fact. What I meant to say is that standard units should be used, and individuals should be left to contextualise said units of their own accord, instead of it being done for them.
Pedantic: 1 atm = 1.01325 bar (exactly). They're nearly equivalent units, even more so when you consider that Earth's atmosphere varies by more than 1.325% on a given day. But in a strict sense they're not the same.
The US survey foot, as you probably know having brought it up but elaborating for the audience, is the old US foot before it was averaged with the British foot to create the international foot. It is 500000/499999 international feet.
I’m actually Canadian. I like that joke because I think a lot of units are useful for calculations but completely unintuitive. If I had instead said it was 9.3 megapascals and left it at that it wouldn’t have given most readers an intuition for how much pressure that really is. The pressure inside a steam engine boiler comparison, while not perfect, gives a bit better frame of reference because people have some intuition for how powerful steam engines are.
Oh and I like the unit ‘bar’ because it’s the customary unit for espresso machine pressure (and I’m an espresso nerd with my own machine at home). Espresso machines make espresso by forcing hot water through a puck of finely ground coffee at a pressure between 8 and 12 bar. If you’ve ever worked with an espresso machine, you’ll have an intuitive sense for how much pressure that is (a lot). Venus having 10 times that pressure is also impressive.
I like measurements that are immediate and visual. Your comparison to boiler pressure was a perfect example of that (I also immediately imagined the boiler blowing up :) )
_On_ Venus? That seems unlikely; if anything it'd be _above_ Venus (there's a not-that-absurd argument that sections of Venus's atmosphere are far more hospitable than, say, Mars, and of course this tickles sci-fi writers' love of big airships, so it comes up a lot in fiction).
(Though I assume that even then, the whole surface exploding would be undesirable.)
The toughest thing for making Venus habitable is that its day is 243 Earth days. It's like roasting on a slow spit.
I think we should be aggressively seeding its atmosphere with extremophiles, hoping that something evolves to transform all that free energy into life.
That's assuming that there isn't already something out there, e.g. floating in the more manageable atmosphere. There's beings living in or close to thermal vents in Earth's oceans or in acid pools in Yosemite, so it would be possible for things to survive there as well.
If you watch it you'll hear the story of Venus plate tectonics and they present it in such a way as to make it one of the most fascinating mysteries of the solar system.
It's a documentary worth settling in to for an hour on the couch and enjoying the ride.
Anyhow my theory (as a highly qualified astro geologist) is that Venus, whilst being the same size as the Earth does not have plate tectonics because it does not have a moon which pulls the magma around the planet, stirring it up nicely. Instead, Venus surface just cools off and then gets hot again periodically. I hope you didn't buy the astro geologist line.
MIT scientists have previously shown that if this stinky, poisonous gas were ever detected on a rocky, terrestrial planet, it could only be produced by a living organism there.
( I'm assuming your credentials as an astro biologist are fine... )
Based on my impeccable qualifications as an Astro biologist, it seems unlikely to me there’s life there given the intense heat and crushing pressure but lots of people like to be optimistic about it.
If that is what I think it is, I'm pretty sure that isn't considered strong evidence anymore. I don't know exactly why, I just remember there's reason to be skeptical of it and the reason seemed pretty valid.
Something to do with the amounts being minuscule, the fact that there are valid explanations outside of biology that could create such a chemical.
I'll have to look for the source, but they did follow-up observations with a different instrument and detected phosphine again. In spite of the wide-spread scepticism, the observation appears to be real. The source of the phosphine can be debated, of course.
Both the James Clerk Maxwell Telescope (JCMT) in Hawaii, and the Atacama Large Millimeter Array (ALMA) observatory in Chile made the spectral observation inferred to be phosphine (aka 'signature of life') described in the headline and lede.
so what? We havent sent much of anything to Venus in the past 30 years. There isnt TOO much to add.
Parker Solar probe I believe made a few passes in the last couple years that added some terrain mapping and a few headlines about life possibilities based on some spectrographic reads that ended up being debunked. But I dont think much else has been done.
All that is to say, something from 30 years ago is probably still pretty relevant for Venus.
I've often wondered how important our moon was to Earth developing life. The moon gives us tides which creates areas where sea life can learn to adapt to land, but I've also wondered if the moon had any effect on keeping the Earth's core and mantle hot and fluid.
If moonless Venus also has volcanic activity, then clearly our moon is not necessary for that. But if Earth has tectonic activity while Venus doesn't, then why that difference? I would have expected tectonic and volcanic activity to go hand in had, but clearly that's not necessarily the case.
The difference isn't active tectonics vs not. It's plate tectonics vs stagnant lid tectonics.
The presence of water at many fault lines is essential to allowing plates to stay separate and move relative to each other. The subduction and divergence is then essential to gas exchange between atmosphere and mantle that gives the system stabilizing inertia.
It's unclear what came first on Venus, but it's pretty clear that high temperature, boiling water (a greenhouse gas!), and stagnant lid tectonics all provided positive feedback to each other, with the boiling off of water probably kicking the process into high gear.
Subducting oceanic plates drag down with them a great deal of water. When that flashes to steam as it hits magma and the mantle, tremendous pressures are generated. Many volcanoes (though not all) are in this regard "steam engines", where much of the driving pressure is a consequence of subducted ocean water, and possible some innate crustal water, interacting with geothermal heat. I'm supposing this is why steam is a major factor in many volcanic eruptions.
Reminds me of the Vajont Dam disaster, in which filling of a reservoir behind a newly constructed dam lead to catastrophic collapse of a mountainside in the Italian Alps, where layered sedimentary limestone separated by thin layers of clay became unstable as the clay was wetted and lubricated by the reservoir.
Shortly before 11 pm on 9 October 1963, a two-kilometer-long landslide triggered a 250m (850 ft) megatsunami. That killed a number of engineers who'd gathered on top of the dam to observe its filling, as well as around 2,000 inhabitants of villages adjacent to and downstream of the reservoir, most notably Longarone which was virtually scrubbed from the map.
The dam itself was virtually undamaged by the incident, save the topmost metre or so of nonstructural masonry.
Silica's melting point is lowered when mixed with water, so oceanic faults can have actual molten magma lubricating and weakening the fault line. Otherwise, you'd have the stronger malleable solid mantle at the joint, and lose much more energy whenever the fault tried to move.
Having at least some faults that slippery is necessary to keep the system from locking up.
The Moon's impact (so to speak) is undoubtedly profound, in many ways.
Tidal forces are likely a factor in plate tectonics, though sources I'm familiar with suggest that virtually all the energy is contributed, roughly equally, by latent heat of gravitational formation (that is, the kinetic energy of source material colliding) and radioactive decay. What I've seen in estimates of tidal energy as a renewable source are that it is vastly smaller than even geothermal generally, as well as unconcentrated (natural geothermal vents, volcanoes, geysers, etc., provide zones in which significant direct energy capture is possible upwards of 1 GW in a single zone, as with the California Geysers geothermal generation project).
Tides are absolutely a factor in ocean cycles (and early in the Moon's lifespan would have been cataclysmic as the Moon orbited far closer to the Earth). Lunar cycles are evident in life-forms everywhere (the shell of the nautilus, for example, records the duration of the month throughout geological time, covered in Daniel Botkin's The Moon in the Nautilus Shell <https://www.danielbbotkin.com/books/the-moon-in-the-nautilus...>). Cycles of moonlight and darkness drive many animal behaviours. The giant-impactor hypothesis of lunar formation would have had a profound effect in the distribution of elements and minerals within the Earth's crust. And that's just off the top of my head as a non-specialist.
We could colonize Venus by sending floating cities. The atmosphere is so dense you could float a large (sealed!) steel container high up in the atmosphere where it’s close to a livable temperature and pressure.
Possibly. But I suspect that old-fashioned "fake gravity via rotation" cities in space would be cheaper, have fewer catastrophic failure modes, and be easy (relatively) to construct in far more desirable locations.
"fake gravity via rotation" cities in space would be cheaper, have fewer catastrophic failure modes, and be easy (relatively) to construct in far more desirable locations.
It would be better to place the rotating cities inside Ceres or other asteroid, so you don't need to build thick walls to stop radiation and meteorites.
Also you are already in a body you can mine and has a small gravity to build farms. Ceres is a good place to have a midway station to send ships further out the solar system. But another nice location would be an asteroid with an elliptic orbit and perihellion near Earth, aphelion near Ceres, that could act as a shuttle.
Venus is "easy" to get to, and that's a major reason for its appeal. You'll also get radiation protection (it has an induced magnetic field), and a leak is less likely to be catastrophic since the pressure outside is about the same as inside, and you get real gravity rather than having to expend the immense resources to try to spin up a whole asteroid. Venus may well turn out to be one of the easiest places in the solar system to settle.
Needing to build buildings the size of football stadiums isn't exactly a significant issue, given we already do that with… football stadiums.
The hard part is "in space", where we need to solve both ISRU and getting there cheaply[0] for this to be anything other than vanity projects.
[0] Starship, if it works as advertised, is a wagon train to the stars — you need it to get going, but you don't want to do the Oregon trail in a wagon train when you have an airline or an interstate highway at your disposal.
Making ferris wheels airtight is somewhat pointless, but would be in certain regards easier in freefall than on the ground as (a) it doesn't need to start off spinning and therefore doesn't need to be stable until it's finished, and (b) there's not going to be the same concerns about metal fatigue because the force isn't going to constantly change direction from the reference frame of any given element.
If that can be balanced against (c) we've barely scratched the surface of space manufacturing and don't know what to expect, remains to be seen.
The London Eye is about 2/3rds of the size of a stadium. In addition, a ferris wheel has nothing like the mass you need to support for a space station.
There is no question that building a rotating structure with that kind of mass at that kind of scale rotating at those kinds of speeds is going to create significant novel engineering problems.
Those problems become even bigger when you consider that this structure has to be built in space (we've never built anything of this size in space, let alone tried to spin it up) and you have to solve problems like thermal expansion/contraction that will only get harder with scale.
> The London Eye is about 2/3rds of the size of a stadium. In addition, a ferris wheel has nothing like the mass you need to support for a space station.
You're being too literal, "stadium" isn't an SI unit and 120 metres is bigger than the 112 meters suggested in the article up-thread, so the technicality is not an important point.
Also, the core point is that the tensile strength required is nothing special. Indeed this is why the O'Neill designs are the size they are (8x32 km) and you only need to jump to mass-produced carbon nanotubes for the much larger and more ridiculous McKendree cylinder (size: Russia).
> kinds of speeds is going to create significant novel engineering problems
No doubt, novel things usually do even on the ground, that's why civil engineering is the discipline that it is — but can you name any not already faced by, say, suspension bridges?
In particular: what is speed supposed to do in this case, given its in space, and chosen specifically for 1g acceleration like everything on Earth is anyway?
The point of my comment was that there are implications for the human body with the rotational artificial gravity. The video sums it up pretty nicely with a live experiment in 6min.
I saw the video when it was new, and knew about Coriolis force since my childhood when my father (incorrectly) told me the thing about the direction water rotates when draining.
Its importance goes down when the parent object gets bigger compared to the contained object, which is why it's not important to draining but is important to hurricanes.
This was already treated in the 1970s NASA studies of space-colony concepts. In the first one they underestimated the problem, iirc, and had to recommend larger rings in the second.
It's hard to conceive how a space station with just some 100m of radius can even be useful. The artificial gravity is very likely far from a bottleneck.
Well, gotta start somewhere, and that's probably a decent size for a hotel.
I'm not sure how useful these would really be, of course. Only way to tell is to wait and see, unless you're working for Bezos or Musk and they're paying you to actually do the thing.
(Heck, part of me thinks they could be so terrible in practice that they are one of the fillers in the Fermi paradox, but I really should tidy up those thoughts into a proper blog post rather than ramble in a comment…)
It can be almost arbitrarily long on the other axis.
Though without specific use-cases to ask questions about — and I have none — you're right by default: just because it's possible, doesn't make it good for anything specific.
AFAIK Venus has a similar composition to Earth so it should have enough nickel. The rotation rate of 243.025 days per Earth day on Venus is the real problem for it having a magnetosphere.
Unlike the earth which has all sorts of tectonics going on and constant interruptions releasing pressure, on Venus the pressure just builds and builds until the crust can't take it anymore and it just pops and you get volcanic activity unlike anything we could probably even imagine.
Then it cools and the pressure starts building yet again.
I am 100% confident that should human society settle on the planet we will totally ignore the fact that's going to happen one day and it will be a amazing catastrophe when it finally does occur.