Or some nano-designed organism/machine... however that could turn into opening Pandora's box.

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I'm resurrecting this thread because I've just had a random thought about terraforming Venus and I don't want to spam people by creating a new thread.

Most biological/chemical process that are proposed would either not work or be extremely hard, seeing as the atmosphere of Venus is already in its most stable chemical configuration and will tend to go back to that if you make any changes.

So how about skipping chemical processes and going for nuclear ones. If atoms in the Venusian atmosphere were to capture neutrons and decay into other elements, the process would essentially be irreversible. Also, the compounds they currently form which are causing us problems (such as CO2) would be destroyed.

Of course, it depends what exact changes would take place to the atmosphere if it were saturated with neutrons, and it would require a powerful source of them.

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I can't imagine how to make enough neutrons to get rid of a millionth part of the atmosphere of Venus, but it might work. The atmosphere has some sulpher in H2SO4 which could become two of the lighter elements if you can get a sulpher nucleus to absorb 1, 2 or 3 more neutrons. The carbon nucleus can't split into anything else but lithium, boron, and beryilium. The beryilium and it's compounds are very toxic, but perhaps it would be rare. In each case, I think, the pico size particle would react chemically with the carbon dioxide to form a compound which is solid, but would remain suspended in the atmosphere for years, because of it's extremely small size. The neutrons would react preferentially with the elements in the atmosphere, but I don't know the preference. The most abundent element in the atmosphere is oxygen, so there is way too much oxygen, so hopefully most of the oxygen would be converted to a solid oxygen compound or another element. Venus has about the same amount of nitrogen as Earth, so hopefully most of the nitrogen would remain in the atmosphere. Other elements are trace in the atmosphere, but the neutron caused fission would increase the abundence of most of the elements with smaller atomic numbers than sulpher. I'm calling the emission of a beta particle fission as it lowers the atomic number by one (an oxygen issotope becomes a nitrogen issotope after it emits a beta particle which is a hydrogen nucleus plus an electron or a positron) Large quantities of hydrogen, helium, neon, and nitrogen would cause little mischief. Florine is the only other light element which forms toxic compounds, so hopefully florine and beryilium would be rare.
Neutrons don't travel far in thick gases, so the neutrons would rarely reach the surface, but some of the radioactive isotopes would reach the surface and produce trace amounts of most of the elements. Some of the radio active isotopes would be a problem for millions of years. If I understand the table, I'm looking at, radio active isotopes will be formed from nuetron capture more often than stable isotopes. If so, Venus would be very radioactive for millions of years following this method of reducing the atmosphere. Neil

Couldn't we push asteroids into orbit around Venus and strip off atmosphere?

Could we reflect sunlight onto the night side to keep the temperature rising and expand the atmosphere, allowing the solar wind to blast off the uppermost portion?

I really am more for terraforming Earth though. If we can't get that right, we don't have a prayer at working with Venus or Mars.

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Could you have orbiting stations that dangled large hoses into the atmosphere and suck stuff up? Pumping stuff up from the surface doesn't seem to make sense when you can siphon off the top.

On another note: Is there some industry that could benefit from conditions on Venus?

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Typical asteroids would add as much gas to Venus as they would blow away far enough that Venus would not recature the gas that was blown off. Reflecting sunlight in huge quantities on to the Venus night side should strip off some atmosphere, by the solar wind, but you might have to heat it to about 4000 c to vaporize and ionize the carbon, to get rid of half the atmosphere in a million years.
I don't think a syphon will work, but perhaps an air hose could shoot some atmosphere far enough into space that only half would be recaptured by Venus.
Minor benfits to many processes are likely, but the hostile conditions more than negate any advantage I can think off. We can however build balloon supported habitats in the upper atmosphere of Venus where the temperature is about 12C = 55 degrees f Neil

No, a siphon wouldn't work. The entire planet is surrounded by a vacuum, but its atmosphere stubbonly refuses to be sucked away.

To get the overabundance of CO2 off the planet (and maybe export it to elsewhere in the system, the Moon, for instance, or Mars) you would need to lift the atmosphere physically off the planet. Some sort of dynamic ring system
http://en.wikipedia.org/wiki/Orbital_ring
would probably be the best bet - we are talking about mega-engineering here, but it is a big job, so you need to think big.
Hey- there is lots of carbon in the atmosphere- why not use carbon in the construction of the ring? Carbon nanotubes, Aggregated diamond nanorods, diamond itself, graphene; all materials which might be useful for constructing these megastructures.

The superrotating atmosphere itself could be tapped to supply the rings with power (these devices are active, not passive structures, and require power to stay in the sky; even more if they are used to lift material).
Paul Birch gave some ideas on lifting mass out of Venus' atmosphere in a paper written for the JBIS, available here http://www.paulbirch.net/

Actively extracting atmosphere from the planet may also help to speed up the cooling process; once in space the extracted mass could cool down by radiation.

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Earlier in the thread, I quoted Oberg on the energy issues involved in removing the atmosphere:

Making Venus livable

It takes a lot of energy and impressive hardware.

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There is a lot of energy in the superrotating atmosphere; and I can't think of an easy way to store that energy to use it elsewhere in the Solar System, so it might as well be used on site to help remove the excess CO2. And the oxygen, which might be a worse problem.

Venus is in the state it currently is because it has lost a lot of hydrogen; by adding cometary water, that hydrogen could be replaced- but that also adds extra oxygen which wasn't there before. Some of the CO2 would be absorbed by the crust, to make carbonates- but the excess oxygen might be a problem. I'm pretty sure we can't terraform Venus without adding hydrogen somehow, and the removal of excess gas also looks inevitable, espcially if the hydrogen is added as water ice impactors.

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