Mars cannot be terraformed. It’s too small to hold an atmosphere. Even if we collected the entire asteroid belt and dragged Pluto to Mars, we would only increase its mass by about 5%, which is still too small.
The best we will be able to do is domed cities.
Venus is a better candidate, if we can figure out how to relieve the greenhouse effect.
IOW Mars needs a bubble.
If the Sun starts getting squirrely... being further away from it makes more sense though.
Titan has everything we need in either ice or liquid form, has a megnetosphere, etc... It's just REALLY cold.
Mars will be important... not to terreform, but as a jump off/transfer point.
It’s the solar wind that stripped Mars atmo once it’s core cooled and no longer was generating a large magnetic field to produce a magnetosphere....NASA has a plan to create a large plasma bubble and an artificial magnetosphere. Then Mars could hold an atmosphere it has the mass to hold one and did for a long time while it has the protection of its magnetosphere Mars once had a sense atmo, liquid oceans and was much warmer. It was conducive to life hundreds of millions of years before earth cooled enough to hold liquid water on its surface. It’s entirely possible life evolved there first and we know meteorites have come from Mars to Earth and landed in one piece with the internal temp of the inside not getting above a hundred F from the deep cold of space to touchdown the what pulse is fast and largely contained to the other layers of meteorites.
https://astrobiology.nasa.gov/news/how-to-give-mars-an-atmosphere-maybe/
Get the plasma bubble big enough and you deflect the solar wind in its shadow.
The atmosphere of Venus is basically sulfuric acid and CO2, and the atmospheric pressure is >1300 psi on the surface. That's about twice the pressure in a diesel engine when the piston is at TDC.
Good luck with terraforming that.
Venus is a better candidate, if we can figure out how to relieve the greenhouse effect.
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While surviving 800 F temperatures, sulfuric acid atmosphere, and air pressure equivalent to 15km beneath the Earth’s ocean.