(Im)practical terraforming

[Thesto Neroses]

OK, I like the idea of terraforming other planets in the solar system, but am sadly ill-educated on the practicalities of such an endeavour.

I recall reading in Kim Stanley-Robinson's Mars Trilogy about the removal of a mirror from Mars and it's insertion between Venus and the sun.

So, my question is, would this work? And how quickly would the surface temperature of Venus fall if it had such drastically reduced insolation?

[fried beef sandwich]

It would probably help.... but damn! Eternal darkness!

[Thesto Neroses]

Originally posted by fried beef sandwich
It would probably help.... but damn! Eternal darkness!

Well, just long enough for the CO2 to freeze out of the atmosphere and got rid of somehow (processed into Calcium Carbonate and buried in diamond blocks or something)

After that, maybe you could have a mix of atmospehric gases that produce an earthlike surface temperature, despite proximity to the sun.

Of course, you might have to do something about the fact that Venus' day is longer than it's year.

[Rhaedas]

Mars having a earthlike rotation simplifies its terraforming to one of atmosphere content. Venus has a lot of different issues that would have to be resolved, and probably the biggest one is its rotation (or lack of). It's possible a barrage of calculated impacts could decrease the Venusian day, but there might be easier methods, such as mirroring/blocking sunlight to simulate a 24 hour period. Add to that a near lack of water and overabundance of CO2, and Venus makes Mars seems trivial. I had seen somewhere speculation on using CO2 scouring blimps in the higher parts of Venus, either totally removing the CO2, or just the carbon, and combining the oxygen with imported hydrogen to create rain again, which would eventually help cool the surface. No quick fixes though...Mars will be first, if any planet is terraformed.

It may be possible to live on Venus now though, as long as you stick to the higher atmosphere, where the temperatures and pressures are reasonable. Picture some "Cloud City" type setup, floating above the harsh lower Venusian air.

[Plognark]

I don't know how well mars could be terraformed....it appears that mars is just the wrong composition to hang onto a strong atmosphere.

Not that venus would be a piece of cake or anything; if I had to pick i'll take mars, thanks! :D

[Jack the Bodiless]

I believe the argument for Mars is that it could hang onto a dense atmosphere for a while. An atmosphere that takes millennia to dissipate might be sufficient, if topped up by dropping carbonaceous asteroids into it occasionally.

Does anyone have data on what the atmospheric pressure on Mars would be if all the frozen CO2 at the poles was vaporized?

[butswana]

I think this was in one of Bob Zubrin's books. If the atmospheric pressure of Mars was brought up to 15psi, it would take 10,000 years to dissipate to its current level. If that is true, then it would be easy to manage.

[Nostalgic Pushhead]

I'm writing a story (I think I mentioned it here ages ago; I'm still working on it).

Part of the backstory is the existance of a "Genesis Machine", that is, a giant terraforming thingamajig. Sort of like a giant factory, built in space. When they found an inhospitable planet, they'd park the Genesis machine in its orbit. The machine would be capable of refining matter down to base elements... so it would produce vast amounts of oxygen, nitrogen, water, etc. And then it would dump this stuff, over the course of a few years, or many years, or something, onto the surface of the planet. I guess it would have to extract the planets atmosphere first, I'm not sure how that would be done. And along with the water and gas would be a very large amount of "biomass", generally, as much organic material as possible.

So what I'm asking, is if a planet was at the right distance from its sun, and had suffiencet gravity... if you dumbed a whole bunch of water, biomass and earth-atmosphere onto it, would, given enough time, become hospitable? Could they add large amounts of invertibrates, and build up some food chains to turn the biomass into soil? I realize it could take decades, but is that at all scientifically possible?

I also had the idea of 'partial teraforming', where just a small area of the planet was altered. Of course, they would have to still put in the entire atmosphere, and then there is the problem of water evaporating and being spread across the planet. I was thinking... what if they made a huge crater, and filled it with water. How long would the water last? Could a deep enough water source built on rock hold enough water to last for centuries? I'd imagine that, over time, enough water would evaporate that a natural rain cycle would develop, but in the meantime the people around the source would have an nearly unlimited supply.

Oh, I just thought of something. Because plants are needed to create oxygen... and if only a small part of the planet is teraformed, you could only have so many plants. Because the amount of animals/humans is also small, would this even out?

None of that stuff is *really* important to the plot, so if there are some huge logic flaws, I can drop stuff. According to my timeline the Genesis machine crashes in 2821

[Toto]

I heard a lecture at the Skeptics Society (http://www.skeptic.com) from Robert Zubrin, the head of the Mars Society (http://www.marssociety.org/), who had a plan to terraform Mars. He had a budget worked out, and a timetable and a plan, and it all sounded quite reasonable, almost.

There's an article here:

http://www.wired.com/wired/archive/9.07/mars.html

"I don't think Zubrin's a nut, and I study nuts for a living," says Michael Shermer, editor in chief of Skeptic magazine, who generally supports the Mars Society plan. "He's a zealot, but you have to be in that job. The key to good science is striking a balance between being open-minded and being conscientious, and I think Zubrin does that."