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Interesting that Venus has a near-habitable zone around 50km altitude [1] (air pressure and temperature similar to earth, albeit without oxygen). Venus gravity

Interesting that Venus has a near-habitable zone around 50km altitude [1] (air pressure and temperature similar to earth, albeit without oxygen). Venus gravity is very similar to earth (91% of earth's). Makes me curious about Venus terraforming We've all heard that surface pressure is 80 atmospheres with temperatures that can melt lead (due to high carbon dioxide and powerful greenhouse effect), but I never thought about the temperature and pressure gradient with altitude. Great project to raise awareness of space, and cool judo move against all the interest in Mars From [1]: > According to measurements by the Magellan and Venus Express probes, the altitude from 52.5 to 54 km has a temperature between 293 K (20 °C) and 310 K (37 °C), and the altitude at 49.5 km above the surface is where the pressure becomes the same as Earth at sea level [1] https://en.wikipedia.org/wiki/Atmosphere_of_Venus https://en.wikipedia.org/wiki/Atmosphere_of_Venus

hitpointdrew 3y ago
Pretty sure the high temp, has less to do with the carbon dioxide, and more to do with the fact that the planet rotates so slowly. It takes 243 earth days for one day on Venus.
nielsbot 3y ago
I do love the concept of balloon lofted dwellings on Venus, which i assume would be in this zone? E.g. https://en.wikipedia.org/wiki/High_Altitude_Venus_Operational_Concept https://en.wikipedia.org/wiki/High_Altitude_Venus_Operationa...
dekhn 3y ago
Reminds me of the art from "National Geographic's Picture Atlas of our Universe", including (land-based) Venus lifeforms (https://www.michaelwhelan.com/galleries/our-universe-venusians/ https://www.michaelwhelan.com/galleries/our-universe-venusia...) but given your comment, is more like the jellyblimps and swordtails of Jupiter (https://twitter.com/whelanmichael/status/1568606680992079872 https://twitter.com/whelanmichael/status/1568606680992079872) If those pictures look familiar, it's likely because you grew up in the 70s and read that book, then forgot about it for the next 35 years.
shiroiuma 3y ago
Kurzgesagt has a video about Venus terraforming if you're interested. Basically, it'll take a really long time, require some gigantic mirrors to stop the runaway greenhouse effect and freeze the atmosphere, then mass drivers to shoot it all off the planet, then another parallel project on Europa to use mass drivers to shoot water to Venus. It's way, way beyond our capability. It is possible to build cloud cities on Venus at 50km altitude. The question is: why? What are you going to do there exactly? There's no economic incentive at all, since you can't mine the surface for anything valuable. Who's going to pay for some people to live in a floating colony so far away, one that's completely reliant on resources from Earth to sustain it? At least with Mars, it's somewhat plausible (though not really) to build a mostly self-sustaining colony, and there might (probably not) be some resources worth mining and sending back to Earth. Personally, I think the idea of terraforming planets in this system is just silly and a waste of time to even think about. If you want resources, go to the Moon, and work on capturing and mining asteroids. If you want to make places for people to live that aren't so far away and don't have so many challenges, just build O'neill cylinders. You can keep them close to Earth for easy transit, and build them to precisely replicate Earth-normal habitats unlike terraforming projects. O'neill cylinders may seem like unrealistic sci-fi tech, but they're far more realistic and doable than these terraforming projects. The only place terraforming really makes sense if where there's a planet with similar conditions to Earth: similar mass, day/night cycle, temperature, etc. Such a planet doesn't exist in this system. It might exist in another system, but just traveling to another star system is probably harder than building an O'neill cylinder. The other thing that might make sense for a habitat is hollowing out a small asteroid and then spinning it for spin-gravity, as was depicted in The Expanse (with Eros).
- mcmoor 3y ago
  Ones that are interested in Venus usually are ones that are fed up with the Mars projects and actually I'm one of them. If we want to terraform at all it makes sense to try Venus first and since it's also very hard, well...
  - shiroiuma 3y ago
    It's not just "very hard", it's utterly impossible for a civilization of our level. Making a small colony on Mars is far more doable, even though that's pretty dubious. But Mars at least doesn't have a sulfuric acid atmosphere with crushing deep-sea pressure and a temperature hot enough to melt lead. The idea of terraforming that is just silly. It would be easier to build a generation ship to travel to other star systems.

hitpointdrew 3y ago

Pretty sure the high temp, has less to do with the carbon dioxide, and more to do with the fact that the planet rotates so slowly. It takes 243 earth days for one day on Venus.

nielsbot 3y ago

I do love the concept of balloon lofted dwellings on Venus, which i assume would be in this zone? E.g. https://en.wikipedia.org/wiki/High_Altitude_Venus_Operational_Concept https://en.wikipedia.org/wiki/High_Altitude_Venus_Operationa...

dekhn 3y ago

Reminds me of the art from "National Geographic's Picture Atlas of our Universe", including (land-based) Venus lifeforms (https://www.michaelwhelan.com/galleries/our-universe-venusians/ https://www.michaelwhelan.com/galleries/our-universe-venusia...) but given your comment, is more like the jellyblimps and swordtails of Jupiter (https://twitter.com/whelanmichael/status/1568606680992079872 https://twitter.com/whelanmichael/status/1568606680992079872) If those pictures look familiar, it's likely because you grew up in the 70s and read that book, then forgot about it for the next 35 years.

shiroiuma 3y ago

Kurzgesagt has a video about Venus terraforming if you're interested. Basically, it'll take a really long time, require some gigantic mirrors to stop the runaway greenhouse effect and freeze the atmosphere, then mass drivers to shoot it all off the planet, then another parallel project on Europa to use mass drivers to shoot water to Venus. It's way, way beyond our capability. It is possible to build cloud cities on Venus at 50km altitude. The question is: why? What are you going to do there exactly? There's no economic incentive at all, since you can't mine the surface for anything valuable. Who's going to pay for some people to live in a floating colony so far away, one that's completely reliant on resources from Earth to sustain it? At least with Mars, it's somewhat plausible (though not really) to build a mostly self-sustaining colony, and there might (probably not) be some resources worth mining and sending back to Earth. Personally, I think the idea of terraforming planets in this system is just silly and a waste of time to even think about. If you want resources, go to the Moon, and work on capturing and mining asteroids. If you want to make places for people to live that aren't so far away and don't have so many challenges, just build O'neill cylinders. You can keep them close to Earth for easy transit, and build them to precisely replicate Earth-normal habitats unlike terraforming projects. O'neill cylinders may seem like unrealistic sci-fi tech, but they're far more realistic and doable than these terraforming projects. The only place terraforming really makes sense if where there's a planet with similar conditions to Earth: similar mass, day/night cycle, temperature, etc. Such a planet doesn't exist in this system. It might exist in another system, but just traveling to another star system is probably harder than building an O'neill cylinder. The other thing that might make sense for a habitat is hollowing out a small asteroid and then spinning it for spin-gravity, as was depicted in The Expanse (with Eros).

mcmoor 3y ago
Ones that are interested in Venus usually are ones that are fed up with the Mars projects and actually I'm one of them. If we want to terraform at all it makes sense to try Venus first and since it's also very hard, well...
- shiroiuma 3y ago
  It's not just "very hard", it's utterly impossible for a civilization of our level. Making a small colony on Mars is far more doable, even though that's pretty dubious. But Mars at least doesn't have a sulfuric acid atmosphere with crushing deep-sea pressure and a temperature hot enough to melt lead. The idea of terraforming that is just silly. It would be easier to build a generation ship to travel to other star systems.