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.
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.
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.
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.
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).
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.
https://en.wikipedia.org/wiki/Gerard_K._O%27Neill#Space_colo...
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.
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".