The issue with Venus and Mars is that there is no magnetosphere. Over geological time periods the hydrogen is slowly lost into space. All that CO2 in the atmosphere could become H20 given enough introduced hydrogen, and photosynthesis.
Yes, geologic times, so like 100 million years or more, not relevant to human life timescales. But even Venus has substantial atmosphere still, including substantial amounts of hydrogen still (with enhanced deuterium concentration due to the atmospheric loss… which could actually be worth mining for nuclear power export).
Making a magnetic field on those timescales is easy, tho, compared to the other challenges. If you cool Venus down, you can place superconducting wires around the equator to generate a magnetic field. This is much easier than the terraforming you had to do.
My understanding is, insofar as we're talking about protection from radiation, Venus compensates for its lack of a magnetosphere with incredibly thick atmospheric cover that does the same work, in fact does it better than here on Earth. That's not to say we would say no to a magnetosphere if such a thing could ever be achievable.
Venus has a lot of atmosphere but very little water, maybe 1/1,000,000 as much in the atmosphere as we have in the atmosphere + ocean.
If you are interested in hyperlarge structures you could maybe spread out a really big foil to catch hydrogen from the solar wind and react it with oxygen in one form or another to make a large ocean.
There's a degree of induced magnetosphere on Venus. Coupled with the atmosphere, you're far more shielded from radiation even floating high up in the Venusian atmosphere than on Mars.
It would be a colony constantly depending on Earth supplies and you would be constantly rebuilding it. Just like every other planet, nothing can permanently survive in upper atmosphere. It would be easier to have a massive ISS-style station in orbit, with a tethered cable elevator for research.
Untrue. You can actually mine the Venusian surface for metals. Carbon, hydrogen, oxygen, and nitrogen (the vast majority of the elements used by life) can be extracted from the atmosphere, as well as sulfur. So from an elemental standpoint, it actually could be self-sufficient. Not that you’d WANT to avoid trade with other planets, but it is possible.
It is also possible to terraform Venus, although much more difficult than for Mars.
Terraforming is possible but colonizing worlds hostile to humans has always meant genetic engineering to me. We need to drop the Star Trek idea that we can explore space in the sacks of water we call bodies.
Let's take the idea further, and borrow cstross's belief that canned apes will never colonize or explore anything, and only digital uploads into mechanical bodies will be destined for space.
Terraforming is so conceptual at this point that I wouldn't take a hard stance on either being easier or harder. You never know what a few generations of studies will teach us; and what misconceptions we hold dearly that our descendants will laugh at us for.
At this point we're so deep into the science fiction that it might be easier to just hop into a time machine and colonize Mars before its atmosphere boiled off.
From my experience there is a correlation between people who think science is nonsense while also believing in terraforming. I don’t think anybody can even remotely predict the outcomes of a terraforming project.
Yes, but! It's very hard. But you are a million percent right that the Venusian surface has lots of fantastic metals, largely tied up in basalt and volcanic ash. The bad news to my understanding is that they're kind of pulverized and evenly spread out and requires lots of refining/processing, and not necessarily so much in the way of veins/ore deposits ripe for harvesting (though I could be mistaken).
But back to how hard it is. There's mid-atmosphere winds that are effectively persistent hurricanes. It's hotter than a pizza oven, and the thick co2 air might as well be an ocean, because it has that much crushing force.
In my opinion, people should get excited about the thick atmosphere, because it's also the secret superpower that unlocks all the near term possibilities. Floating in the upper atmosphere is more like being a ship in an ocean, and if we ever got materials strong enough (graphite-carbon composites?) we could do some really cool passive dragnet + air balloon lift kinds of things to recover surface resources and lift them to a hypothetical settlement.
The one need-to-have resource that, as far as I know, there's none of on Venus whatsoever, is iodine. So even in the best case you'd have to import that. Oh, and water. You can get some out of the sulfuric acid rain but probably not as much as you want.
Granted, these are all assuming technology advances and big time scales, but trying to practice a golden rule here and be as charitable to the exercise as possible and not bean soup the discussion to death, which is a pet peeve of mine.
It'd be interesting to try to imagine a Venusian colonization that's like two separated levels: an atmospheric area where most people live and where you grow food, and then a subterranean (yes, yes, sub... aphroditean?) where you mine and so forth, and there are brief, fraught transitions between the two layers but no actual habitation of the surface or lower atmosphere.
> It is also possible to terraform Venus, although much more difficult than for Mars.
We are facing an existential crisis in the form of climate warming on Earth that we are unable to address properly. The thing is, terraforming Earth is the easiest thing to do: we already live on it, it's already liveable. Mars, Venus or any other body in the solar system is magnitudes harder to transform on almost every aspect.
So unless humanity demonstrates it can tackle the easiest terraforming endeavour that be, anything else is firmly in the science fiction realm.
Exactly. I used to be a lifelong fan of anything space. But right now it is limited to people conducting actual science to get a better understanding of our universe. All the dick-swinging billionaires and geopolitical vanity projects of going to the Moon and Mars are utter follies. Every billion spent there, a waste of money that could be better spent. And I am not even talking about outer atmosphere ultra-rich people tourism in literal penis rockets. Utter pollution and waste. Let's wait to colonize other planets until after we get our own house in order.
I really doubt your veracity about this. It’s literally illegal for billionaires to geoengineer the Earth to stop global warming (at least in several states). Doubtless you would also object to that as well. In which case it’s not actually about solving Earth’s problems but about not liking those who are doing it.
Billionaires could trivially fund uncontroversial projects like planting trees or solar electrification, especially in the developing world, both of which would help stop global warming. But I'm not holding my breath waiting for Elon or Larry to start doing either of those things, or anything else that would actually help mitigate or reverse climate change.
Musk could spend 10 or even 100 billion on more down to Earth efforts without affecting his quality of life in the slightest. Instead he's promoting a self-serving idea, one that relies entirely on his own rocket-company infrastructure.
Putting data centers in space is also a dumb idea due to the difficulty of dissipating heat, solar radiation, maintenance challenges and more.
Yes, I don't care about these selfish sociopath billionaires, and certainly wouldn't want them to geoengineer Earth. Perhaps pay their due tax to society would be a better idea. Fixing Earth might include having a system where people don't get to be billionaires and soon trillionaires that dominate the planet.
Geoengineering of Earth is remarkably easy. The reason it’s not already being done is political, not technical or even necessarily economic. For less than NASA’s budget, it’s possible to do things like stratospheric solar radiation management. See: Mount Pinatubo. Some places (Florida, etc) have already made laws prohibiting it.
As far as being science fiction… obviously? Terraforming Venus is a very long term project. It’s scientifically possible but hasn’t already been done. I guess I don’t understand what “science fiction” is supposed to mean. Like, Jules Verne writing about long distance underwater submarines? Trips to the Moon launched from Florida?
It is also possible to terraform Venus, although much more difficult than for Mars.
We’ve not terraformed anything, ever, but now we can compare the difficulty of terraforming of one planet versus another? “It’s possible”? So is turning lead into gold.
I said it was possible. “…fleeting quantities of gold nuclei”, and probably worth far, far less than it cost to make. Given that, I stand by my statement. :-)
> You can actually mine the Venusian surface for metals
By "surface" do you mean the ground of Venus? The odds of a mining operation happening on the ground of Venus seems like science fiction at best, impossible at worst. Between the high winds, corrosive atmosphere, outlandish heat and extreme pressure any vehicle on the surface would be torn to shreds likely within a few hours (which has so far been the case for all landers that actually survived the landing) - and that's not even getting into the idea of getting things off the ground. Extraction from the atmosphere would likely be the only method unless something significant changes with the entire planet. Refining those materials would require a lot of machinery being in Venus's orbit that we'd have to get there, as well. Speaking of the conditions though...
> It is also possible to terraform Venus
Everything is hypothetical at best regarding this and would require a level of time and resources no government nor company would want to invest for an outstanding "maybe".
At 50 km altitude above Venus (where pressure is about 1 bar) you are not really in the "upper atmosphere" as there is still about as much atmosphere above you as on ground level on Earth. So UV radiation is not a problem.
The atmosphere of Venus is just very thick. Also it contains many useful elements, C, O and H, which can be used to build basically anything if you have enough solar energy. The problem is the (comparatively small) amounts of other elements.
From the point of view of exploitable resources, Venus is the opposite of Mars.
On Mars, metals are very abundant and easy to extract, and also minerals suitable for making glass or ceramic materials are abundant, but the raw materials for making food and organic materials, like plastics, are very scarce and expensive to concentrate.
On Venus, there are abundant resources for making organic materials and food (except for a few metallic bioelements required in small quantities, i.e. Fe, Zn, Mn, Cu, Mo, Co), but there are no resources for making metallic, vitreous or ceramic materials.
However, the materials that are missing on Venus are easier to transport from elsewhere, because they are required in smaller quantities and they are dense solids that occupy little volume. If not enough water would be found underground on Mars, that would be really difficult to transport from elsewhere.
> If not enough water would be found underground on Mars, that would be really difficult to transport from elsewhere.
I was under the (uneducated) impression that there was a fair amount of water ice locked up in asteroids that are fairly easy to redirect into a Mars capture orbit.
> would be a colony constantly depending on Earth supplies and you would be constantly rebuilding it
To be fair, this is true for all planets with known science and engineering. I'm not sure it's obvious that Venus (with its higher pressure and better radiation shielding) has fewer fundamental problems than Mars (with its surface that doesn't melt metal).
The results of some experiments done with mice on the ISS have been published recently and they cast doubt about the possibility of living for a long time on the Moon.
For mice, at least a third of the Earth gravity was required to prevent serious health problems and at least two thirds to avoid any health problems.
So it seems that the gravity of Mars is close to the minimum compatible with long-term staying, while that of the Moon is insufficient. Therefore people would have to spend only a limited time on a Moon base, much like on the ISS.
If I remember correctly, the habitable-ish cloud layers have super-fast winds that circle the planet once every 4 days or so. [0]
[0] https://en.wikipedia.org/wiki/Atmospheric_super-rotation
If you could increase rotation somehow and place a moon sizes object in it's orbit, maybe you could improve the magnetosphere and reduce volcanism by inducing plate tectonics.
Every time I read about colonizing another planet, I think about how we correctly don't want to colonize the bottom of the ocean or the Sahara desert because it would be completely uneconomical, and yet either would be much easier than this.
Yeah, and the fact that no one is doing "practice runs" on them is telling how serious any colonization effort really is. Zero chance of a successful mars city if we can't even colonize the trivial in comparison ocean.
I agree. And how all of our meager steps towards trying to learn the pre-requisites of sustainable colonies (eg. closed cycle ecology) have failed miserably. For example Biosphere program (https://en.wikipedia.org/wiki/Biosphere_2 ).
And the only working ecological system we can study is being destroyed by humanity and capital on record pace.
Biosphere 2 had the problem, not least, that it didn't have enough of an atmosphere to buffer swings of CO2 concentration between day and night. It's like "what did they think would happen?"
I think it is more that you need a specific endpoint and a real business plan. Like how could Biosphere 2 have really made money?
A closed loop ecology for, say, survival on Mars, is an interesting question that somebody might need an answer to but there is no reason why it needs to look like the Earth with oceans and all and it might lean heavily on bacteria that live in vats or 24 hour illuminated agriculture or something.
Meanwhile it is not so clear that from a scientific point of view that some experiment in a greenhouse can give conclusive answers about the ecology of the Earth where so much is going on.
That and we'd soon do the same things to a new planet that we're doing to this planet. The more time humanity has to mature from a cooperation-over-conflict perspective (both with each other and other beings/the environment) before it starts spreading to other planets, the better.
It would be akin to a city floating on Earth's open ocean. With all food, household items etc, and even construction materials produced via extraction from the surrounding ocean.
For Earthlings, the open ocean is harder to survive on long-term than deserts like the Sahara. Maybe on par with living off the land on Antarctic. Never mind all that corrosive stuff in Venus' atmosphere.
Doable in theory, yes. But HARD (and then some). That's ignoring the economics of such an enterprise.
On the upside: still easier than interstellar travel.
I think atmospheric extraction is very important and valuable but we'd be missing heavy metals and some critical elements. You do have carbon, oxygen, nitrogen, sulfur, a little bit of hydrogen, a little bit of chlorine and flourine, and you can do a lot with those. Not as much hydrogen as you would want or need.
But potassium, sodium, calcium, magnesium, silica, iron oxides, nickel, titanium etc. are available on the surface.
> It would be akin to a city floating on Earth's open ocean. With all food, household items etc, and even construction materials produced via extraction from the surrounding ocean.
Akin in some senses, but let's not omit that another planet would be far, far more difficult. Humans do live on boats and islands in oceans; we can breathe the air, drink the water (if desalinated), eat the fish, swim, build boats from resources, etc.
There's no reason to colonize the ocean bottom. For one thing, it's completely dark and cold. For another, I don't see any way you could build a spacious structure that could resist the pressure.
I still think humanity's far future is in orbitals in space, not on planets and certainly not on planets as hostile as Venus is. I'm not sure how well living at 50km above the surface would work. You still need a lot of buoyance to float large structures.
The atmosphere is also a solvable problem. One idea I've heard is using so-called "fusion candles". That is a fusion-powered device in the atmosphere that sends waste gas into space and waste matter to the ground in an equilibrium that keeps them airborne, all powered by fusion. You could extract carbon and/or oxygen this way from the plentiful atmospheric CO2.
Still, if you ever got the atmosphere down to a non-hellish level at surface, the surface would still be covered with all sorts of exotics and metals, many of them toxic. You'd probably be looking at geologic timescales to rehabilitate it.
But whenever these terraforming questions come up (often with respect to Mars), people really don't appreciate the scale and the energy budget required. The energy budget is many orders of magntidue what our civilization currently uses. If you have access to that much energy, there are far better options.
space colonization, even if there were habitable planets within our reach, is not possible anymore.
you could, for example, send a million settlers to Kepler-69420, and with the TFR of 1.5 - an unrealistically high number - the colony would be extinct in just a few centuries. 1m becomes 100k in 200 years and 10k in 400 years.
I bet the colonists would be highly (self-)selected for many traits not common in the majority of the population, likely including the willingness to have many children.
I suppose that colonists on other planets, like colonists on other Earth continents, would largely consist of people who are unhappy with the status quo at their origin, and would have some strongly-held ideas about a different way of living.
>likely including the willingness to have many children.
why exactly do you find it likely? on the contrary, most of the colonists would need to be highly educated professionals for the colony to be self-sufficient, so they would be even less likely to have many children than average people.
besides, in very near future, the TFR of 1.5 will pass for "willingness to have many children".
I don't think that the highly educated people who would join the expedition would at the same time be happy to se their colony die out, and would find it too onerous to have children and pass their knowledge and fervor to the next generations.
Again, I don't think that a self-sustained colony on another planet would be organized by Earth governments, and by people who are happy to live on Earth. I bet on projects like (the declared) Musk's Mars colony, and even more, on religious groups (remember Mayflower). It takes a lot of grit to leave the comforts of Earth and go live in highly inhospitable and limiting conditions of another world, for life. Do not compare it to traits of a typical middle-class college-educated coastal city dweller. Those are going to be very different people, with very different views on everything, including fertility and raising children.
From my (admittedly limited) knowledge of the research, education of women is the best correlate for lower birth rates. Once women have other options, staying home and popping out babies is less popular.
I don't know exactly how that might work in the scenarios we are discussing though.
If anyone wants breadcrumbs, I just did a deep dive and there are a couple of promising technologies that could terraform Venus on roughly a human timescale of 100 years:
* Sun shade/sail near L1 tipped up to 35 degrees to remain still: 5 micron polymer film (1.5-3.5 billion tons or 10-25 million SpaceX Starship launches at 150 tons each) or 50 layer graphene (15 thousand tons or 100 launches). Liquid CO2 ocean forms at 31 C or 88 F, or dry ice glaciers at -78 C or -108 F result in nitrogen atmosphere dropped from 92 times pressure to close to Earth's pressure. Shade rotation can simulate a 24 hour day.
* Comets to increase water and spin rate: 50-100 100 km diameter comets from Kuiper Belt at 30 AU, nuclear rocket using 1% of water to gravitationally slingshot comets by planets over 20-100 years to impact at equator, resulting in 50 day retrograde or 64 day prograde rotation (down from 243 days). Decreases temperature and sulphuric acid enough for microbes to start fixing CO2 and acid.
The "hard" parts are getting bots into orbit to blow graphene bubbles to form a honeycomb, and inventing open-ended fusion rockets to avoid containment issues.
I think the sun shade is probably how we'll slow global climate change until we can plant the 1-10 trillion trees it will take to reverse it (mechanical carbon capture can't be scaled enough practically), but I digress.
Note that the blocker is actually getting to low Earth orbit (LEO) since delta V is straightforward with ion engines. That will arguably be a solved problem once big "dumb" rockets like Starship scale. I'm a big fan of JP Aerospace's airship to orbit concept and other magnetohydrodynamic (MHD) craft, but it's unclear if they will be able to achieve heavy lift. Aerospike engines and exotic rockets are being evolved by AI currently.
Forgotten: genetically modified algae-like organisms that would float at the habitable-ish altitude due to having a gas bubble. These organisms should consume sunlight and transform gaseous substances into something more solid/liquid to rain it down onto the surface, thus making the atmosphere less thick and more transparent. Bonus points for binding and removing chlorine and leaving oxygen intact.
thijson | 8 hours ago
Robotbeat | 8 hours ago
Making a magnetic field on those timescales is easy, tho, compared to the other challenges. If you cool Venus down, you can place superconducting wires around the equator to generate a magnetic field. This is much easier than the terraforming you had to do.
21asdffdsa12 | 8 hours ago
pavel_lishin | 7 hours ago
glenstein | 7 hours ago
PaulHoule | 7 hours ago
If you are interested in hyperlarge structures you could maybe spread out a really big foil to catch hydrogen from the solar wind and react it with oxygen in one form or another to make a large ocean.
vidarh | 3 hours ago
1970-01-01 | 8 hours ago
https://en.wikipedia.org/wiki/Exposing_Microorganisms_in_the...
Robotbeat | 8 hours ago
It is also possible to terraform Venus, although much more difficult than for Mars.
p2detar | 8 hours ago
pavel_lishin | 7 hours ago
gwbas1c | 8 hours ago
Terraforming is so conceptual at this point that I wouldn't take a hard stance on either being easier or harder. You never know what a few generations of studies will teach us; and what misconceptions we hold dearly that our descendants will laugh at us for.
marginalia_nu | 7 hours ago
airstrike | 7 hours ago
vjvjvjvjghv | 6 hours ago
surgical_fire | 7 hours ago
We can't even properly terraform inhospitable places within Earth.
Hell, if anything we are very quickly un-terraforming Earth into a place inhospitable to human life.
t_mahmood | 7 hours ago
We are failing the great filter very hard.
vjvjvjvjghv | 6 hours ago
zabzonk | 5 hours ago
zqna | 6 hours ago
surgical_fire | 6 hours ago
Robotbeat | 5 hours ago
glenstein | 7 hours ago
But back to how hard it is. There's mid-atmosphere winds that are effectively persistent hurricanes. It's hotter than a pizza oven, and the thick co2 air might as well be an ocean, because it has that much crushing force.
In my opinion, people should get excited about the thick atmosphere, because it's also the secret superpower that unlocks all the near term possibilities. Floating in the upper atmosphere is more like being a ship in an ocean, and if we ever got materials strong enough (graphite-carbon composites?) we could do some really cool passive dragnet + air balloon lift kinds of things to recover surface resources and lift them to a hypothetical settlement.
The one need-to-have resource that, as far as I know, there's none of on Venus whatsoever, is iodine. So even in the best case you'd have to import that. Oh, and water. You can get some out of the sulfuric acid rain but probably not as much as you want.
Granted, these are all assuming technology advances and big time scales, but trying to practice a golden rule here and be as charitable to the exercise as possible and not bean soup the discussion to death, which is a pet peeve of mine.
mmooss | 6 hours ago
aetherson | 4 hours ago
0xAFFFF | 6 hours ago
We are facing an existential crisis in the form of climate warming on Earth that we are unable to address properly. The thing is, terraforming Earth is the easiest thing to do: we already live on it, it's already liveable. Mars, Venus or any other body in the solar system is magnitudes harder to transform on almost every aspect.
So unless humanity demonstrates it can tackle the easiest terraforming endeavour that be, anything else is firmly in the science fiction realm.
rapnie | 6 hours ago
Robotbeat | 5 hours ago
dboreham | 5 hours ago
teachrdan | 4 hours ago
WalterBright | 4 hours ago
brendoelfrendo | 3 hours ago
teachrdan | 2 hours ago
Putting data centers in space is also a dumb idea due to the difficulty of dissipating heat, solar radiation, maintenance challenges and more.
Robotbeat | 24 minutes ago
rapnie | an hour ago
Robotbeat | 5 hours ago
As far as being science fiction… obviously? Terraforming Venus is a very long term project. It’s scientifically possible but hasn’t already been done. I guess I don’t understand what “science fiction” is supposed to mean. Like, Jules Verne writing about long distance underwater submarines? Trips to the Moon launched from Florida?
mikestew | 4 hours ago
We’ve not terraformed anything, ever, but now we can compare the difficulty of terraforming of one planet versus another? “It’s possible”? So is turning lead into gold.
benced | 4 hours ago
mikestew | 4 hours ago
jsbisviewtiful | 4 hours ago
By "surface" do you mean the ground of Venus? The odds of a mining operation happening on the ground of Venus seems like science fiction at best, impossible at worst. Between the high winds, corrosive atmosphere, outlandish heat and extreme pressure any vehicle on the surface would be torn to shreds likely within a few hours (which has so far been the case for all landers that actually survived the landing) - and that's not even getting into the idea of getting things off the ground. Extraction from the atmosphere would likely be the only method unless something significant changes with the entire planet. Refining those materials would require a lot of machinery being in Venus's orbit that we'd have to get there, as well. Speaking of the conditions though...
> It is also possible to terraform Venus
Everything is hypothetical at best regarding this and would require a level of time and resources no government nor company would want to invest for an outstanding "maybe".
https://en.wikipedia.org/wiki/Terraforming_of_Venus
seszett | 8 hours ago
The atmosphere of Venus is just very thick. Also it contains many useful elements, C, O and H, which can be used to build basically anything if you have enough solar energy. The problem is the (comparatively small) amounts of other elements.
adrian_b | 8 hours ago
On Mars, metals are very abundant and easy to extract, and also minerals suitable for making glass or ceramic materials are abundant, but the raw materials for making food and organic materials, like plastics, are very scarce and expensive to concentrate.
On Venus, there are abundant resources for making organic materials and food (except for a few metallic bioelements required in small quantities, i.e. Fe, Zn, Mn, Cu, Mo, Co), but there are no resources for making metallic, vitreous or ceramic materials.
However, the materials that are missing on Venus are easier to transport from elsewhere, because they are required in smaller quantities and they are dense solids that occupy little volume. If not enough water would be found underground on Mars, that would be really difficult to transport from elsewhere.
pavel_lishin | 7 hours ago
I was under the (uneducated) impression that there was a fair amount of water ice locked up in asteroids that are fairly easy to redirect into a Mars capture orbit.
neaden | 6 hours ago
FrustratedMonky | 7 hours ago
But wonder if a floating balloon contraption isn't more likely than a base on Mars. Which is more deadly?
Venus seems to have more potentially useful compounds in the atmosphere.
marcosdumay | 6 hours ago
Venus atmosphere has the right amounts of radiation, temperature, and pressure. And close to the right gravity.
JumpCrisscross | 5 hours ago
To be fair, this is true for all planets with known science and engineering. I'm not sure it's obvious that Venus (with its higher pressure and better radiation shielding) has fewer fundamental problems than Mars (with its surface that doesn't melt metal).
1970-01-01 | 5 hours ago
adrian_b | 2 hours ago
For mice, at least a third of the Earth gravity was required to prevent serious health problems and at least two thirds to avoid any health problems.
So it seems that the gravity of Mars is close to the minimum compatible with long-term staying, while that of the Moon is insufficient. Therefore people would have to spend only a limited time on a Moon base, much like on the ISS.
JumpCrisscross | 24 minutes ago
Artemis aims to establish lunar and Martian colonies. Not self-sufficient settlements. That's still at least a generation away, probably two or three.
whoisthemachine | 8 hours ago
3form | 7 hours ago
ultratalk | 4 hours ago
kraquepype | 3 hours ago
empath75 | 8 hours ago
missingdays | 8 hours ago
freedomben | 8 hours ago
dullcrisp | 8 hours ago
atrus | 8 hours ago
sl-1 | 8 hours ago
And the only working ecological system we can study is being destroyed by humanity and capital on record pace.
PaulHoule | 7 hours ago
amanaplanacanal | 4 hours ago
PaulHoule | an hour ago
A closed loop ecology for, say, survival on Mars, is an interesting question that somebody might need an answer to but there is no reason why it needs to look like the Earth with oceans and all and it might lean heavily on bacteria that live in vats or 24 hour illuminated agriculture or something.
Meanwhile it is not so clear that from a scientific point of view that some experiment in a greenhouse can give conclusive answers about the ecology of the Earth where so much is going on.
RankingMember | 8 hours ago
RetroTechie | 7 hours ago
For Earthlings, the open ocean is harder to survive on long-term than deserts like the Sahara. Maybe on par with living off the land on Antarctic. Never mind all that corrosive stuff in Venus' atmosphere.
Doable in theory, yes. But HARD (and then some). That's ignoring the economics of such an enterprise.
On the upside: still easier than interstellar travel.
glenstein | 7 hours ago
But potassium, sodium, calcium, magnesium, silica, iron oxides, nickel, titanium etc. are available on the surface.
mmooss | 5 hours ago
> It would be akin to a city floating on Earth's open ocean. With all food, household items etc, and even construction materials produced via extraction from the surrounding ocean.
Akin in some senses, but let's not omit that another planet would be far, far more difficult. Humans do live on boats and islands in oceans; we can breathe the air, drink the water (if desalinated), eat the fish, swim, build boats from resources, etc.
WalterBright | 4 hours ago
okokwhatever | 8 hours ago
jmyeet | 7 hours ago
I still think humanity's far future is in orbitals in space, not on planets and certainly not on planets as hostile as Venus is. I'm not sure how well living at 50km above the surface would work. You still need a lot of buoyance to float large structures.
The atmosphere is also a solvable problem. One idea I've heard is using so-called "fusion candles". That is a fusion-powered device in the atmosphere that sends waste gas into space and waste matter to the ground in an equilibrium that keeps them airborne, all powered by fusion. You could extract carbon and/or oxygen this way from the plentiful atmospheric CO2.
Still, if you ever got the atmosphere down to a non-hellish level at surface, the surface would still be covered with all sorts of exotics and metals, many of them toxic. You'd probably be looking at geologic timescales to rehabilitate it.
But whenever these terraforming questions come up (often with respect to Mars), people really don't appreciate the scale and the energy budget required. The energy budget is many orders of magntidue what our civilization currently uses. If you have access to that much energy, there are far better options.
[1]: https://www.youtube.com/watch?v=BI-old7YI4I
perilunar | 6 hours ago
https://en.wikipedia.org/wiki/Gerard_K._O%27Neill#Space_colo...
Ajedi32 | 4 hours ago
mcc1ane | 6 hours ago
b65e8bee43c2ed0 | 6 hours ago
you could, for example, send a million settlers to Kepler-69420, and with the TFR of 1.5 - an unrealistically high number - the colony would be extinct in just a few centuries. 1m becomes 100k in 200 years and 10k in 400 years.
nine_k | 5 hours ago
I suppose that colonists on other planets, like colonists on other Earth continents, would largely consist of people who are unhappy with the status quo at their origin, and would have some strongly-held ideas about a different way of living.
b65e8bee43c2ed0 | 5 hours ago
why exactly do you find it likely? on the contrary, most of the colonists would need to be highly educated professionals for the colony to be self-sufficient, so they would be even less likely to have many children than average people.
besides, in very near future, the TFR of 1.5 will pass for "willingness to have many children".
nine_k | 4 hours ago
Again, I don't think that a self-sustained colony on another planet would be organized by Earth governments, and by people who are happy to live on Earth. I bet on projects like (the declared) Musk's Mars colony, and even more, on religious groups (remember Mayflower). It takes a lot of grit to leave the comforts of Earth and go live in highly inhospitable and limiting conditions of another world, for life. Do not compare it to traits of a typical middle-class college-educated coastal city dweller. Those are going to be very different people, with very different views on everything, including fertility and raising children.
ShinyLeftPad | 4 hours ago
amanaplanacanal | 4 hours ago
I don't know exactly how that might work in the scenarios we are discussing though.
b65e8bee43c2ed0 | 2 hours ago
antiquark | 5 hours ago
readthenotes1 | 3 hours ago
slim | 5 hours ago
ck2 | 4 hours ago
Humans cannot survive long-term space travel, yet, the technology does not exist
The radiation alone will kill you and then there is the problem is you will go blind from changes in your body and brain fluids
zackmorris | 4 hours ago
* Sun shade/sail near L1 tipped up to 35 degrees to remain still: 5 micron polymer film (1.5-3.5 billion tons or 10-25 million SpaceX Starship launches at 150 tons each) or 50 layer graphene (15 thousand tons or 100 launches). Liquid CO2 ocean forms at 31 C or 88 F, or dry ice glaciers at -78 C or -108 F result in nitrogen atmosphere dropped from 92 times pressure to close to Earth's pressure. Shade rotation can simulate a 24 hour day.
* Comets to increase water and spin rate: 50-100 100 km diameter comets from Kuiper Belt at 30 AU, nuclear rocket using 1% of water to gravitationally slingshot comets by planets over 20-100 years to impact at equator, resulting in 50 day retrograde or 64 day prograde rotation (down from 243 days). Decreases temperature and sulphuric acid enough for microbes to start fixing CO2 and acid.
The "hard" parts are getting bots into orbit to blow graphene bubbles to form a honeycomb, and inventing open-ended fusion rockets to avoid containment issues.
5 cm by 50 cm graphene sheet grown in 20 minutes:
https://www.nature.com/articles/srep21152.pdf (warning PDF)
Direct fusion drive:
https://www.sciencedirect.com/science/article/pii/S009457652... (PDF available)
Magnetic mirror concept for open-ended fusion rocket:
https://en.wikipedia.org/wiki/Magnetic_mirror
Magnetic reconnection thruster:
https://www.youtube.com/watch?v=caM94mem5K4
I think the sun shade is probably how we'll slow global climate change until we can plant the 1-10 trillion trees it will take to reverse it (mechanical carbon capture can't be scaled enough practically), but I digress.
Note that the blocker is actually getting to low Earth orbit (LEO) since delta V is straightforward with ion engines. That will arguably be a solved problem once big "dumb" rockets like Starship scale. I'm a big fan of JP Aerospace's airship to orbit concept and other magnetohydrodynamic (MHD) craft, but it's unclear if they will be able to achieve heavy lift. Aerospike engines and exotic rockets are being evolved by AI currently.
WalterBright | 4 hours ago
Trees, on the other hand, can scale, and they get their energy from the sun.
nine_k | 2 hours ago