[RockinRight]

Venus would be much more difficult. There's no water on Venus (Mars has some in the icecaps and probably underground) and has 1000 times the atmosphere we'd need, not to mention it's all CO2. Plus, since it is closer to the Sun, it would be difficult to cool it off enough to be habitable.

[eagle11]

True, plus Venus is in near "tidal lock" with the Sun, its day is actually longer than its year. This would present climatic extremes for humans even if we could change Venus to our liking. Mars, although its surface gravity is 38% of Earth's, is more suitable for the near-term. But I believe (the romantic idea) that we'll sidestep these worlds, due to some future propulsion tech. that will permit settling other star systems.

[mvpel]

There have been some interesting proposals regarding Venus to hit it with ice asteroids to introduce water, blast away some of the excess atmosphere, cool the surface, and increase its rotational period from its current 116 days to something a bit more practical.

[FreedomCalls]

There's no water on Venus

There's a lot of water on Venus isn't it? It's water vapor trapped in the atmosphere though. There is no liquid water on Venus however.

Image of the surface of Venus from the Russian Venera-13 lander.

[orionblamblam]

> Venus would be much more difficult.

In it's way, Venus would be *less* difficult. Notice where Venus' atmosphere reaches one standard atmosphere of pressure... and what the temperature is there.

> There's no water on Venus

There are oceans of water on Venus... trapped in the sulphuric acid. Relatively easily cracked and utilized.

> 1000 times the atmosphere we'd need, not to mention it's all CO2

All to the better.

> it would be difficult to cool it off enough to be habitable.

No need to do so whatsoever.

[JimRed]

Plus, since it is closer to the Sun, it would be difficult to cool it off enough to be habitable.

I heard somewhere that Venus' surface temperature is around 800 degrees.

[FierceDraka]

Cooling Venus could be accomplished by unfurling a giant shade or filter and hanging it between Venus and the sun.

By comparison, terraforming Venus makes the idea of terraforming Mars look as simple as doing some landscaping work around the yard.

One brute-force method I came up with to thin-out the Venusian atmosphere is to simultaneously air-burst tens of thousands of high-megaton fusion bombs and just blast all that CO2 out into space. What a spectacular view that would be from Earth! Venus flaring up like a nova, then turning into the biggest damned comet ever seen as its atmosphere is blown outward by the solar wind.