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https://en.wikipedia.org/wiki/Exposing_Microorganisms_in_the...
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.
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.
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.
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).
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.
Artemis aims to establish lunar and Martian colonies. Not self-sufficient settlements. That's still at least a generation away, probably two or three.
It is also possible to terraform Venus, although much more difficult than for Mars.
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.
I would argue that it is very much opposite. Venus has already 80% mass of Earth. Mars on other hand have not much different gravity than that of Moon and Moon is much closer to Earth if you plan to make something suitable for older folks that look for lighter gravity.
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.
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?
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.
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
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.
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.
We are failing the great filter very hard.
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.
Venus atmosphere has the right amounts of radiation, temperature, and pressure. And close to the right gravity.
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.
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.
I've touched this idea before: https://news.ycombinator.com/item?id=26575155
https://en.wikipedia.org/wiki/Gerard_K._O%27Neill#Space_colo...
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 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.
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".
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.
* 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.
Trees, on the other hand, can scale, and they get their energy from the sun.
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
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.
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.
And the only working ecological system we can study is being destroyed by humanity and capital on record pace.
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