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Would you rather be surrounded by very thin CO2 of Mars or clouds of sulfuric acid of Venus? And no possibility to live on the surface? At least we know how t

Would you rather be surrounded by very thin CO2 of Mars or clouds of sulfuric acid of Venus? And no possibility to live on the surface? At least we know how to transform CO2 into oxygen. Mars just seems orders of magnitude more friendly.

Arnavion 12y ago
I imagine Venus being closer to the Sun (and having a higher temperature in general due to the greenhouse effect of its atmosphere) makes it easier to generate usable energy there, RTGs notwithstanding.
aetherson 12y ago
Venus has a LOT more CO2 than Mars does. And the band that people are envisioning putting the aerosats in has, well, less sulfuric acid than does the denser lower atmosphere. Honestly, probably the realistic view is that it never makes sense to colonize, or even send long-term human presence to, any planet besides Earth. But to the extent that we want to dream of human presence on another planet, I think that the big obstacle to Venus is not the hostility of the upper atmosphere, it's the difficulty in getting any non-gaseous resources out of it. At the very least, it seems like sending a robotic balloon probe to Venus to try to tool around in the upper atmosphere for an extended period of time is at least as worthwhile as sending another lander to Mars.
- _rpd 12y ago
  > it never makes sense to colonize, or even send long-term human presence to, any planet besides Earth I don't know, establishing a second, independent biosphere is sound from a risk management standpoint.
  - celticninja 12y ago
    I agree, I think those in the other camp are the ones that only calculate whether there would be a financial benefit and return from the project.
    - TeMPOraL 12y ago
      Economy is an engine of progress, but some people raise it to the level of a God. It's a tool, not a justification. We shouldn't limit our actions only to those that turn profit, 'lest we turn into mindless drones generating entropy without much purpose.
  - dalke 12y ago
    It would be much cheaper to establish a dozen independent biospheres here on Earth than one off Earth. Put one in the Canadian Shield, another under the Australian desert, etc. If scattered well, several should survive even a Chicxulub-class event. But I suspect you mean something different than independent biospheres. If so, what risks are you thinking of?
    - tlb 12y ago
      Most people who have ever tried living in an isolated biosphere on earth decided, after some number of months, that cities and trees and sky were pretty desirable, opened the airlock and left. Possibly it would work on another planet with no return vehicle.
      - dalke 12y ago
        In any case, the first step would be to develop a long-term, viable independent biosphere. We haven't yet figured out that one. Once we get that working, we need enough excess free capacity to raise and educate children to be the next generation of biosphere caretakers. We're nowhere close.
    - _rpd 12y ago
      > several should survive even a Chicxulub-class event That's an interesting proposal. I'd love to read a study on that. > But I suspect you mean something different than independent biospheres. If so, what risks are you thinking of? Well there are degrees of independence. Perhaps "isolation" in the systems engineering sense is a better term. There are a lot of high-risk probabilities that arise as technology advances - and the Fermi paradox isn't encouraging about our chances. For some example risks, let's say grey goo, cybernetically enforced self-destructive tyranny and unexpected stable artificial black hole. In some case, the light-minutes of separation may make the difference. It might make more sense to build an artificial orbital habitat at L5 or the like, but these seem so fragile compared to biospheres that could be constructed on Mars. Being out of the gravity well is a huge advantage, but the gravity on Mars is low enough that space elevators become a real possibility. Perhaps Ceres is a good compromise - lots of water, metal rich asteroids all around.
- unabridged 12y ago
  >Honestly, probably the realistic view is that it never makes sense to colonize, or even send long-term human presence to, any planet besides Earth. I think it could make sense when we have robots that are able to mine material and construct habitats without requiring human supervision. Just build the robots, drop them off on Venus, Mars, etc, then come back in 30 years and sell condos.
  - scentoni 12y ago
    And hope they don't discover the [Zeroth Law](https://en.wikipedia.org/wiki/Three_Laws_of_Robotics#Zeroth_Law_added https://en.wikipedia.org/wiki/Three_Laws_of_Robotics#Zeroth_...)
- grondilu 12y ago
  > At the very least, it seems like sending a robotic balloon probe to Venus to try to tool around in the upper atmosphere for an extended period of time is at least as worthwhile as sending another lander to Mars. Exactly. Enough with Mars already. Red sky, red sand and red rocks : it gets old, frankly.
- stcredzero 12y ago
  > I think that the big obstacle to Venus is not the hostility of the upper atmosphere, it's the difficulty in getting any non-gaseous resources out of it. We can get non-gaseous resources out of Venus accessible asteroids. Venus could supply two things -- a beautiful and relatively friendly place to live and also fluorine condensed out of its atmosphere. I could envision huge aerostat supported structures hundreds of kilometers long that house electromagnetic accelerators to launch raw materials into orbit. Rotating tethers could deposit cargo carriers into the Venusian atmosphere at hypersonic speeds, to deploy ballutes and slow down through aerobraking and then to float awaiting retrieval. In doing so, the tethers would re-accelerate themselves to haul other cargo up from hypersonic aircraft. Maybe it's not economically and politically feasible now or ever, but it's tons of fun to think about. This sort of thing also demonstrates that it's not physically impossible.
- userulluipeste 12y ago
  "Honestly, probably the realistic view is that it never makes sense to colonize, or even send long-term human presence to, any planet besides Earth." The sole point is the experience of colonizing other planet. We're not looking to get there for the resources (stop for a second and just think out of the box), we're looking to get there to be able to live there as a species.
Amezarak 12y ago
> At least we know how to transform CO2 into oxygen. That's so, but the atmosphere on Mars is so thin it's not as if you can step outside there either - you'd die quickly as it's well below the Armstrong limit. You still need a full-body pressure suit on Mars. Venus, FWIW, is 96.5% CO2 and has a surface pressure of 93 bar. That's a lot of oxygen if you just want to make some for your space station. Personally I hold out hope for terraforming Venus. Adding gravity or atmosphere to Mars seems like it'd be much more difficult.
- SapphireSun 12y ago
  They were talking about adding a jet to pump CO2 out of the atmosphere. Is there a chance you could direct the jet such that it intercepts Mars in a useful way? Then you get to rebalance both the planets atmospheres at once. However, Mars has pretty weak gravity so even if you could, I don't know if it would stick around.
  - scarmig 12y ago
    Depends on the timescale. Mars obviously has an atmosphere half-life much shorter than Earth's. At the same time, if its lifetime is a million or even a couple thousand years, it might be entirely suitable for terraforming for humans, depending on the rate at which we can replenish it. Of course, at some point we have to ask questions about how renewable a resource various elements are...
henkboyd 12y ago
At 52km you don't need heating, and in the case of a breach the clouds would stay mostly out because of equal pressures on both sides of the dwelling. A scientific outpost, like those in Antarctica, would be highly appealing. For permanent settlement, Mars takes the cake.
_rpd 12y ago
> At 50 kilometers up, Venus is remarkably Earth-like ... The atmospheric pressure is a comfortable one bar, the gravity about 90 percent that of Earth's, and temperatures fall within a hospitable range of 0-50 degrees Celsius. Nothing to sneeze at, but I don't think it is an exaggeration to say that a flying habitat of sufficient reliability is orders of magnitude more difficult. Are there studies that suggest otherwise?
ohitsdom 12y ago
The gravity is what makes Venus appealing. Mars' gravity is so weak, and studies so far show that is a big problem on the human body.
- danielweber 12y ago
  We don't know anything about what 3/8g does to the human body.
  - userulluipeste 12y ago
    We don't know indeed, but I'd rather bet my horses on the 9/10g than on 3/8g.

Arnavion 12y ago

I imagine Venus being closer to the Sun (and having a higher temperature in general due to the greenhouse effect of its atmosphere) makes it easier to generate usable energy there, RTGs notwithstanding.

aetherson 12y ago

Venus has a LOT more CO2 than Mars does. And the band that people are envisioning putting the aerosats in has, well, less sulfuric acid than does the denser lower atmosphere. Honestly, probably the realistic view is that it never makes sense to colonize, or even send long-term human presence to, any planet besides Earth. But to the extent that we want to dream of human presence on another planet, I think that the big obstacle to Venus is not the hostility of the upper atmosphere, it's the difficulty in getting any non-gaseous resources out of it. At the very least, it seems like sending a robotic balloon probe to Venus to try to tool around in the upper atmosphere for an extended period of time is at least as worthwhile as sending another lander to Mars.

_rpd 12y ago
> it never makes sense to colonize, or even send long-term human presence to, any planet besides Earth I don't know, establishing a second, independent biosphere is sound from a risk management standpoint.
- celticninja 12y ago
  I agree, I think those in the other camp are the ones that only calculate whether there would be a financial benefit and return from the project.
  - TeMPOraL 12y ago
    Economy is an engine of progress, but some people raise it to the level of a God. It's a tool, not a justification. We shouldn't limit our actions only to those that turn profit, 'lest we turn into mindless drones generating entropy without much purpose.
- dalke 12y ago
  It would be much cheaper to establish a dozen independent biospheres here on Earth than one off Earth. Put one in the Canadian Shield, another under the Australian desert, etc. If scattered well, several should survive even a Chicxulub-class event. But I suspect you mean something different than independent biospheres. If so, what risks are you thinking of?
  - tlb 12y ago
    Most people who have ever tried living in an isolated biosphere on earth decided, after some number of months, that cities and trees and sky were pretty desirable, opened the airlock and left. Possibly it would work on another planet with no return vehicle.
    - dalke 12y ago
      In any case, the first step would be to develop a long-term, viable independent biosphere. We haven't yet figured out that one. Once we get that working, we need enough excess free capacity to raise and educate children to be the next generation of biosphere caretakers. We're nowhere close.
  - _rpd 12y ago
    > several should survive even a Chicxulub-class event That's an interesting proposal. I'd love to read a study on that. > But I suspect you mean something different than independent biospheres. If so, what risks are you thinking of? Well there are degrees of independence. Perhaps "isolation" in the systems engineering sense is a better term. There are a lot of high-risk probabilities that arise as technology advances - and the Fermi paradox isn't encouraging about our chances. For some example risks, let's say grey goo, cybernetically enforced self-destructive tyranny and unexpected stable artificial black hole. In some case, the light-minutes of separation may make the difference. It might make more sense to build an artificial orbital habitat at L5 or the like, but these seem so fragile compared to biospheres that could be constructed on Mars. Being out of the gravity well is a huge advantage, but the gravity on Mars is low enough that space elevators become a real possibility. Perhaps Ceres is a good compromise - lots of water, metal rich asteroids all around.
unabridged 12y ago
>Honestly, probably the realistic view is that it never makes sense to colonize, or even send long-term human presence to, any planet besides Earth. I think it could make sense when we have robots that are able to mine material and construct habitats without requiring human supervision. Just build the robots, drop them off on Venus, Mars, etc, then come back in 30 years and sell condos.
- scentoni 12y ago
  And hope they don't discover the [Zeroth Law](https://en.wikipedia.org/wiki/Three_Laws_of_Robotics#Zeroth_Law_added https://en.wikipedia.org/wiki/Three_Laws_of_Robotics#Zeroth_...)
grondilu 12y ago
> At the very least, it seems like sending a robotic balloon probe to Venus to try to tool around in the upper atmosphere for an extended period of time is at least as worthwhile as sending another lander to Mars. Exactly. Enough with Mars already. Red sky, red sand and red rocks : it gets old, frankly.
stcredzero 12y ago
> I think that the big obstacle to Venus is not the hostility of the upper atmosphere, it's the difficulty in getting any non-gaseous resources out of it. We can get non-gaseous resources out of Venus accessible asteroids. Venus could supply two things -- a beautiful and relatively friendly place to live and also fluorine condensed out of its atmosphere. I could envision huge aerostat supported structures hundreds of kilometers long that house electromagnetic accelerators to launch raw materials into orbit. Rotating tethers could deposit cargo carriers into the Venusian atmosphere at hypersonic speeds, to deploy ballutes and slow down through aerobraking and then to float awaiting retrieval. In doing so, the tethers would re-accelerate themselves to haul other cargo up from hypersonic aircraft. Maybe it's not economically and politically feasible now or ever, but it's tons of fun to think about. This sort of thing also demonstrates that it's not physically impossible.
userulluipeste 12y ago
"Honestly, probably the realistic view is that it never makes sense to colonize, or even send long-term human presence to, any planet besides Earth." The sole point is the experience of colonizing other planet. We're not looking to get there for the resources (stop for a second and just think out of the box), we're looking to get there to be able to live there as a species.

Amezarak 12y ago

> At least we know how to transform CO2 into oxygen. That's so, but the atmosphere on Mars is so thin it's not as if you can step outside there either - you'd die quickly as it's well below the Armstrong limit. You still need a full-body pressure suit on Mars. Venus, FWIW, is 96.5% CO2 and has a surface pressure of 93 bar. That's a lot of oxygen if you just want to make some for your space station. Personally I hold out hope for terraforming Venus. Adding gravity or atmosphere to Mars seems like it'd be much more difficult.

SapphireSun 12y ago
They were talking about adding a jet to pump CO2 out of the atmosphere. Is there a chance you could direct the jet such that it intercepts Mars in a useful way? Then you get to rebalance both the planets atmospheres at once. However, Mars has pretty weak gravity so even if you could, I don't know if it would stick around.
- scarmig 12y ago
  Depends on the timescale. Mars obviously has an atmosphere half-life much shorter than Earth's. At the same time, if its lifetime is a million or even a couple thousand years, it might be entirely suitable for terraforming for humans, depending on the rate at which we can replenish it. Of course, at some point we have to ask questions about how renewable a resource various elements are...

henkboyd 12y ago

At 52km you don't need heating, and in the case of a breach the clouds would stay mostly out because of equal pressures on both sides of the dwelling. A scientific outpost, like those in Antarctica, would be highly appealing. For permanent settlement, Mars takes the cake.

_rpd 12y ago

> At 50 kilometers up, Venus is remarkably Earth-like ... The atmospheric pressure is a comfortable one bar, the gravity about 90 percent that of Earth's, and temperatures fall within a hospitable range of 0-50 degrees Celsius. Nothing to sneeze at, but I don't think it is an exaggeration to say that a flying habitat of sufficient reliability is orders of magnitude more difficult. Are there studies that suggest otherwise?

ohitsdom 12y ago

The gravity is what makes Venus appealing. Mars' gravity is so weak, and studies so far show that is a big problem on the human body.

danielweber 12y ago
We don't know anything about what 3/8g does to the human body.
- userulluipeste 12y ago
  We don't know indeed, but I'd rather bet my horses on the 9/10g than on 3/8g.