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Mars is definitely the easiest place to colonize, by far. It's much closer than the gas giants, there's no craft capable of taking people to Saturn even devised

Mars is definitely the easiest place to colonize, by far. It's much closer than the gas giants, there's no craft capable of taking people to Saturn even devised, let alone constructed. Meanwhile, we have SpaceX actively building a rocket for Martian colonization. Second, the Venusian atmosphere is oppressive as hell, you'll not be solving that problem anytime soon, as we can't even solve Earth's much easier atmospheric GHG problem. Martian colonization will be tough. 30% gravity, 3% atmospheric pressure, radiation, very cold, very dry... however, building a base is conceivable and we think we know how to do it.

tekkk 7y ago
True Venus' atmosphere is quite hostile, but from what I briefly read Venus quite probably have had a similar atmosphere with Earth (along with Mars) in the early days, before the runaway green-house effect got the best of it, so at least in theory it should be possible to transform it back. With autonomous robots perhaps it could be done in a span of million years. Maybe. A relatable analogue might be removing liquid from a glass with a tiny straw. Yet I'd think it is easier to remove, than to add material when speaking about terraforming.
- JoeAltmaier 7y ago
  I've often wondered if crashing a metropolis-sized piece of ice into Venus might help? Deflected from Saturn's rings or some such. The water vapor could cool it/reflect sunlight.
  - npongratz 7y ago
    I doubt increasing albedo would help much. Venus already has the highest albedo of any planet in our solar system (at 0.75, versus, for perspective, our moon's 0.12), due to its effectively-100% sulfuric acid cloud cover: https://sciencing.com/albedo-planets-5203.html https://sciencing.com/albedo-planets-5203.html https://www.universetoday.com/36833/albedo-of-venus/ https://www.universetoday.com/36833/albedo-of-venus/ Also, I doubt an insignificant chunk of ice (relatively speaking) could help cool it, or increase albedo. I think the first order of business on Venus, if one wanted to colonize the surface (rather than colonize the atmosphere, which I think is doable), would be to "harvest" the gases of the atmosphere and thin it out to something more resembling Earth's.
  - throwaway5752 7y ago
    It's not a question of cooling it. It went into a runwaway greenhouse effect (https://en.wikipedia.org/wiki/Runaway_greenhouse_effect https://en.wikipedia.org/wiki/Runaway_greenhouse_effect) and it lacks hydrogen. All the hypothetical oceans oxygen bonded with carbon and hydrogen/water vapor was blown off by solar wind. The underlying cause was the loss of the protective magnetosphere. Also, you are probably looking more to continent or small moon size quantities of ice (if that even works, and if the magnetosphere issue was somehow addressed) that metropolis.
  - JdeBP 7y ago
    Have you considered how much kinetic energy it would have, coming all of the way down the well from Saturn?
    - JoeAltmaier 7y ago
      Enough to ionize the water molecules into H and O? Which returns hydrogen to the atmosphere, which is the missing component causing the runaway greenhouse effect?
rbanffy 7y ago
> SpaceX actively building a rocket for Martian colonization. It's unknown whether it is capable of protecting the human cargo on its way to Mars. Maybe a design with habitation encased in the propellant tanks is a better idea for longer transits. In any case, Starship is well positioned for Earth and Moon travels, as well as for sending equipment to LEO and the Moon.
- btkramer9 7y ago
  Worst case radiation they'll receive is comparable to if they've been smoking cigarettes the whole trip. That's pretty damn good if you ask me
- ggffryuuj 7y ago
  This is just silly. Of course it’s known if we can transport humans to mars. The answer is yes. The only question is how much it will cost. All you have to do is surround the craft with mass. It doesn’t even have to be attached to the craft. The cost of giving the mass enough energy to get out of orbit and over to mars is the only question.
LargoLasskhyfv 7y ago
Is it? https://en.wikipedia.org/wiki/Martian_soil#Toxicity https://en.wikipedia.org/wiki/Martian_soil#Toxicity

tekkk 7y ago

True Venus' atmosphere is quite hostile, but from what I briefly read Venus quite probably have had a similar atmosphere with Earth (along with Mars) in the early days, before the runaway green-house effect got the best of it, so at least in theory it should be possible to transform it back. With autonomous robots perhaps it could be done in a span of million years. Maybe. A relatable analogue might be removing liquid from a glass with a tiny straw. Yet I'd think it is easier to remove, than to add material when speaking about terraforming.

JoeAltmaier 7y ago
I've often wondered if crashing a metropolis-sized piece of ice into Venus might help? Deflected from Saturn's rings or some such. The water vapor could cool it/reflect sunlight.
- npongratz 7y ago
  I doubt increasing albedo would help much. Venus already has the highest albedo of any planet in our solar system (at 0.75, versus, for perspective, our moon's 0.12), due to its effectively-100% sulfuric acid cloud cover: https://sciencing.com/albedo-planets-5203.html https://sciencing.com/albedo-planets-5203.html https://www.universetoday.com/36833/albedo-of-venus/ https://www.universetoday.com/36833/albedo-of-venus/ Also, I doubt an insignificant chunk of ice (relatively speaking) could help cool it, or increase albedo. I think the first order of business on Venus, if one wanted to colonize the surface (rather than colonize the atmosphere, which I think is doable), would be to "harvest" the gases of the atmosphere and thin it out to something more resembling Earth's.
- throwaway5752 7y ago
  It's not a question of cooling it. It went into a runwaway greenhouse effect (https://en.wikipedia.org/wiki/Runaway_greenhouse_effect https://en.wikipedia.org/wiki/Runaway_greenhouse_effect) and it lacks hydrogen. All the hypothetical oceans oxygen bonded with carbon and hydrogen/water vapor was blown off by solar wind. The underlying cause was the loss of the protective magnetosphere. Also, you are probably looking more to continent or small moon size quantities of ice (if that even works, and if the magnetosphere issue was somehow addressed) that metropolis.
- JdeBP 7y ago
  Have you considered how much kinetic energy it would have, coming all of the way down the well from Saturn?
  - JoeAltmaier 7y ago
    Enough to ionize the water molecules into H and O? Which returns hydrogen to the atmosphere, which is the missing component causing the runaway greenhouse effect?

rbanffy 7y ago

> SpaceX actively building a rocket for Martian colonization. It's unknown whether it is capable of protecting the human cargo on its way to Mars. Maybe a design with habitation encased in the propellant tanks is a better idea for longer transits. In any case, Starship is well positioned for Earth and Moon travels, as well as for sending equipment to LEO and the Moon.

btkramer9 7y ago
Worst case radiation they'll receive is comparable to if they've been smoking cigarettes the whole trip. That's pretty damn good if you ask me
ggffryuuj 7y ago
This is just silly. Of course it’s known if we can transport humans to mars. The answer is yes. The only question is how much it will cost. All you have to do is surround the craft with mass. It doesn’t even have to be attached to the craft. The cost of giving the mass enough energy to get out of orbit and over to mars is the only question.

LargoLasskhyfv 7y ago

Is it? https://en.wikipedia.org/wiki/Martian_soil#Toxicity https://en.wikipedia.org/wiki/Martian_soil#Toxicity