Terraforming Venus, the hard (fun) way

[DerpenWolf]

So normally when I see threads talking about living on or in the clouds of Venus I can't help but laugh, however I've been thinking and am now wondering if we could terraform Venus if we were a little (lot) less subtle about it. I came to these thoughts after realizing that Venus is really the only other body in the solar system with a solid surface and mass close to that of earth. Knowing Venus pretty much matches the definition of hell I pretty much came to the conclusion that the only way we could terraform it would be if we were to smash stuff into the planet at really high speeds. Basically you would start of by flinging a largish number of solid asteroids at venus in such a way that they may help boost it's orbit slightly and so they blow away some of the atmosphere. You could finish off by launching a few water ice comets (big ones) at the planet do it has some water. In the end you would want enough atmospheric pressure to prevent the water from evaporating and you want to cool the core to reduce the amount of volcanic activity ( maybe some of the materials blasted into space would turn into a small moon or to if the asteroids were big enough). So I'm just curious on how well this would work, could we get an earth like planet or would we be stuck with a volcanic wasteland?

Edit/clarification thing

-I never intended the orbital boost given by impacting asteroids to amount to much, whether it be a meter or a mile every little bit helps

-Comets/water-ice bodies would be used later once the planet reached a state where water could be supported as a liquid if not a solid in some areas

-I didn't intend on removing enough of Venus's atmosphere to make it the same pressure as earth's, if it needs to be a bit thicker or thinner to allow the planet to be more habitable then so be it.

-This wouldn't be cheap or necessarily fast (you will have wait awhile for the big rocks to reach their destination and for the planet to settle down)

-A big asteroid that causes the planets internals (and most likely external) structure to shift significantly is not at all bad. Remember for the most part we don't really care about "preserving" the planet, for all we care we are building a new one from old base materials

-Bigger rocks = more fun/change (probably)

-For the most part we would just want to use asteroids and comets that already have a elliptical orbit that meets the inner planets, Sorry Halley (But really, if we find something that has an orbit that goes out to the Ort cloud/Kruiper belt and it is usable it may be very useful)

-More stuff when I remember what I forgot while typing this

Edited April 9, 2014 by DerpenWolf

[christok]

Adding water would worsen rather than improve the greenhouse problem. I have a more fun suggestion.

Venus lacks a magnetic field due to its entire core being in a single phase (unlike the solid inner and molten outer core of Earth), probably solid because it has already frozen. It also has too much atmosphere. And it lacks a large moon, which may or may not be needed. Earth doesn't have these problems and is a little larger to boot, on account of a "giant impact" with a Mars-sized body in the distant past.

So the plan is, we go looking for some convienently Mars-sized body lying around the solar system...

[Starwhip]

"...Conveniently Mars-sized..."

Well, screw Mars. We don't need you anymore.

[-Velocity-]

So normally when I see threads talking about living on or in the clouds of Venus I can't help but laugh

Why? People laughed at the idea of flying to the Moon, and then, we did it. 80% nitrogen, 20% oxygen is a LIFTING gas on Venus:

CO2 = molecular weight: 12*2 + 16 = 40

80% N2 + 20% O2 (roughly the composition of air) = avg molecular weight: 0.8*(14*2) + 0.2*(16*2) = 28.8.

So you only need to fill your habitat with breathable air and it will float. If there is not breathable air in it, then everyone is dead anyway.

The hard part of it is that there are not accessible raw materials to build a habitat out of on Venus. That might eventually be possible to overcome, although that's unlikely for a long time.

As to the rest of your ideas, they are not feasible. Yes, you could move Venus if you slammed ENOUGH rocks into it. However, if you're going to use each rock only once, I doubt there are enough asteroids in the entire solar system to move Venus' orbit enough to make it habitable. The total combined mass of all the asteroids is VERY SMALL. For example, the entire combined mass of the asteroid belt is only 4% of the mass of the Moon.

However, if you re-use your asteroids, then you can move Venus over a long enough period. If you send enough asteroids past Venus, using Venus' gravity to gravitationally brake the asteroids into lower orbits, you WILL eventually boost Venus to a significantly higher orbit.

Your problems do not end there, though. First off, Venus is well very far outside the habitable zone. Earth is inside the habitable zone, near the inner edge. So what are you going to do with Earth? You'd have to move Earth, too. I doubt that Sol's habitable zone is large enough to fit two Earth mass planets in stable orbits, but I could be wrong. Even if it is possible to fit two plants, your problems are more than doubled, because not only will you need to move two planets, not one, but you'll radically change Earth's environment, too.

Oh and finally, Venus lacks a magnetic field, and it has an extremely slow, retrograde spin... not ideal.

By far, the best way to terraform Venus is to use solar shades to reduce the apparent brightness of the Sun. This effectively allows you to ignore habitable zone concerns and make the temperature on Venus whatever you desire it to be, without having to move it at all. And considering that your solar shades probably only need to be a few dozen microns thick (if that!), it will take very little physical matter and resources (at least compared to some huge asteroid redirecting scheme) to affect this change.

[TheGatesofLogic]

Yup, earth is a very lucky planet indeed, having the magnetic field it does. The fact of the matter is that rocky planets tend NOT to have strong magnetic fields or high core temperatures this late in their lifetime. Earth, being the more massive body in the collision, managed to absorb the core of the mars-sized world it collided with, spewing out mostly just the lighter surface elements to for the moon as we know it. As a result the earth has a core with a relatively high concentration of radioactive materials providing an excellent thermal energy supply that has outlasted all of the other rocky worlds around us, which in turn provides the energy required to support the earth's magnetic field, keeping us nice and safe from solar radiation.

[Dispatcher]

As it happens, there is another Mars sized body in the solar system: Mercury. Their mass is similar. Why waste Mars when "all you have to do" is slam Mercury at Venus and see what happens?

Yup.

[Tommygun]

Well if we can ever create self replicating factories, perhaps we can cover Venus's surface with factories to convert most of the air into oxygen and solid carbon.

The carbon could be stored as a solid underground or shot into space. You would have to mine comets for the nitrogen and water.

As mentioned above, use a solar shade or gravity tractor technique to slowly pull Venus to a new orbit.

No magnetic field is still an issue, but possibly bio-engineering plants and animals that can take the radiation may be a way to go.

It would never be a self sustaining system and would need constant maintenance.

Humans would need to live in shielded cities with limited time in the "country" or be bio-engineered themselves.

I'm not a big fan of bio-engineered people myself, as I worry about changes becoming unstable after a few generations.

[elanachan]

There seems to be some debate on which planets are in the habitable zone, I've been told that earth, venus and mars are all within the habitable zone, and the reason why venus is in the state that it's in is largely due to the lack of a magnetic field, while mars' atmosphere has thinned too much to support more than perhaps the most basic life forms. For the purpose of what I'm talking about, the habitable zone is band of distance from a star (in this case our sun), in which a planet with ideal conditions could support life (any life) without artificial manipulation. By the way, I know that this is off topic, but I've heard theories that a gas giant within the habitable zone of a star could have the potential to support some form of life, the most probable being microscopic in size.

[Idobox]

Well if we can ever create self replicating factories, perhaps we can cover Venus's surface with factories to convert most of the air into oxygen and solid carbon.

The carbon could be stored as a solid underground or shot into space. You would have to mine comets for the nitrogen and water.

As mentioned above, use a solar shade or gravity tractor technique to slowly pull Venus to a new orbit.

No magnetic field is still an issue, but possibly bio-engineering plants and animals that can take the radiation may be a way to go.

It would never be a self sustaining system and would need constant maintenance.

Humans would need to live in shielded cities with limited time in the "country" or be bio-engineered themselves.

I'm not a big fan of bio-engineered people myself, as I worry about changes becoming unstable after a few generations.

There's plenty of nitrogen on Venus, not enough hydrogen (still a lot though), and far too much CO2.

A better idea would be to keep the carbon and launch the oxygen to outer space.

Now, we need self replicating things that consume CO2 and turn it into carbon and O2.

Also, getting resources from the surface is not that hard. The temperatures are high, but there are industrial processes taking place in harsher conditions. The hardest part will be throwing all that excess O2 to space.

[shynung]

Now, we need self replicating things that consume CO2 and turn it into carbon and O2.

.....Plants?

[R0cketC0der]

As to the rest of your ideas, they are not feasible. Yes, you could move Venus if you slammed ENOUGH rocks into it. However, if you're going to use each rock only once, I doubt there are enough asteroids in the entire solar system to move Venus' orbit enough to make it habitable. The total combined mass of all the asteroids is VERY SMALL. For example, the entire combined mass of the asteroid belt is only 4% of the mass of the Moon.

Small mass isn't a problem if you slam them in fast enough. Throw them into it at 0.99999c and you have it moved to a new orbit in with only a few asteroids. However, this still doesn't take care of the other problems and you might end up with a few craters and possibly even a few moons moons.

Please don't tell me that this is too unrealistic, the whole idea behind moving Venus orbit is unrealistic. Also there will be no difference in total fuel expended wether you are slamming a few ones at insane speeds into it or lots of ones at reasonable speeds.

[-Velocity-]

It's all a silly, unrealistic discussion. Venus will simply never be moved in its orbit, because of Earth. Moving Venus out to a point where it no longer receives too much solar radiation would destabilize the orbits of both Earth AND Venus.

Earth, however, could be reasonably moved outward a bit in its orbit, if there is anyone around in 500 million or a billion years who is interested in keeping Earth habitable a bit longer. (If there is still a flourishing biosphere on Earth at that time, I think there will be someone around, because over the last few hundred million years, the overall trend has been that animals have continuously gotten smarter and smarter. No species, at least that I know of, have evolved towards greater stupidity.) As many people already know, the Sun is slowly brightening, and that will probably render Earth uninhabitable before other vital processes like plate tectonics and the carbon cycle are "scheduled" to shut down. So maybe if you "just" move Earth outward by another 5-10 million km, you can extend the habitability of Earth by like, a billion years.

Edited April 9, 2014 by |Velocity|

[R0cketC0der]

It's all a silly, unrealistic discussion. Venus will simply never be moved in its orbit, because of Earth. Moving Venus out to a point where it no longer receives too much solar radiation would destabilize the orbits of both Earth AND Venus.

Earth, however, could be reasonably moved outward a bit in its orbit, if there is anyone around in 500 million or a billion years who is interested in keeping Earth habitable a bit longer. (If there is still a flourishing biosphere on Earth at that time, I think there will be someone around, because over the last few hundred million years, the overall trend has been that animals have continuously gotten smarter and smarter. No species, at least that I know of, have evolved towards greater stupidity.) As many people already know, the Sun is slowly brightening, and that will probably render Earth uninhabitable before other vital processes like plate tectonics and the carbon cycle are "scheduled" to shut down. So maybe if you "just" move Earth outward by another 5-10 million km, you can extend the habitability of Earth by like, a billion years.

Actually earth won't become inhabitable because of the sun brightening. As you may or may not know, the earth is slowly getting tidally locked with the moon. This will make earth inhabitable before the sun brightened enough. On one side of the planet it will be extremely cold and on the other it would be incredibly hot. In the few areas with habitable temperatures there will be extreme winds due to pressure exchange inside the atmosphere.

EDIT: I did some research and this turns out to be wrong. I did misunderstand something I once read.

Edited April 9, 2014 by R0cketC0der

[-Velocity-]

Actually earth won't become inhabitable because of the sun brightening. As you may or may not know, the earth is slowly getting tidally locked with the moon. This will make earth inhabitable before the sun brightened enough. On one side of the planet it will be extremely cold and on the other it would be incredibly hot. In the few areas with habitable temperatures there will be extreme winds due to pressure exchange inside the atmosphere.

Incorrect. I've heard that myth before, but the fact is that the length of time it would take to tidally lock the Earth to the Moon is FAR beyond the lifetime of the Sun. So the Earth will be destroyed by the red giant Sun long, long long before it ever gets a chance to tidally lock with the Moon.

[SargeRho]

That's not correct. The moon will escape before the Earth becomes tidally locked to the Moon, and the Sun will go Red Giant before the Moon escapes.

[-Velocity-]

That's not correct. The moon will escape before the Earth becomes tidally locked to the Moon, and the Sun will go Red Giant before the Moon escapes.

Interesting- so the Moon would have to move so far away from Earth to absorb enough rotational energy to tidally lock that it would be beyond Earth's Hill sphere?

I haven't found the scientific source, but this article matches what I remember hearing before- that geologists had studied rocks laid down in tidal areas and determined that around 2 billion years ago, the days were only 18 hours long. If that represented a linear change- if the Moon were NOT actually moving further away from the Earth- it would mean that the day lengthens by 3 hours every 1 billion years. In actuality, the Moon is getting further away as it absorbs Earth's rotational angular momentum, so the effect is getting weaker and weaker as time goes by. But, just assuming that it WASN'T getting weaker and weaker, then it would still take around (27.3*24 - 24)/3 = 210 BILLION YEARS for the Earth to tidally lock with the Moon. As a more realistic number, I think I remember reading many years ago that it would take well over a trillion years for the Earth to tidally lock with the Moon.

But, this is the first time I ever remember hearing that the Moon would actually escape from Earth before it would tidally lock. I'll see if I can look into it further when I get the chance. If it turns out to be true, thank you very much SargeRho for teaching me something new! Not like it's actually useful information though, since it will (probably) not happen anyway (as the Earth is currently predicted to be consumed by the red giant Sun)

Edited April 9, 2014 by |Velocity|

[-Velocity-]

Actually earth won't become inhabitable because of the sun brightening. As you may or may not know, the earth is slowly getting tidally locked with the moon. This will make earth inhabitable before the sun brightened enough. On one side of the planet it will be extremely cold and on the other it would be incredibly hot. In the few areas with habitable temperatures there will be extreme winds due to pressure exchange inside the atmosphere.

EDIT: I did some research and this turns out to be wrong. I did misunderstand something I once read.

That's OK. I first read about Earth tidally locking with the Moon probably back in like, 1999ish in an article by Bob Berman in Astronomy magazine, and he was claiming that it would actually happen. (He even went further, claiming that after tidal locking had occurred, the process would begin to reverse as the Earth slowly tried to tidally lock with the Sun, and that eventually, the Moon would crash into Earth!).

So, not everything you read is true. Perhaps with a long enough time scale, Bob Berman would be proven right (as long as the Moon doesn't escape first as SargeRho suggested could happen), BUT our Sun is not a red dwarf. I hear that in some textbooks, they STILL claim that glass slowly and measurably flows at room temperature, and that's why old stained glass windows are thicker at the bottom- even though this has been repeatedly shown to be false!!!

Anyway, this brings to mind an idea for a thread we could start- "Common Science Myths". We could cover the flowing glass myth, the myth that airplane wings get their lift from Bernoulli's principle, the Earth-Moon tidal locking, etc. It would be interesting to see how many of them there are, and what they are.

Edited April 9, 2014 by |Velocity|

[DerpenWolf]

OK, so I just got a chance to check in on this thread and I have to say thank you for you input so far. I do however feel the need to clarify a few things such as that when I mentioned having the asteroids hit Venus so it boosted the planets orbit I was not actually intending for the orbit to change much whatsoever!!! Mainly what I meant was that if you can have an asteroid hit Venus in such a way that it boosts the planet to a higher orbit, whether that distance be a meter or a mile, go for it. It doesn't have to be anything significant, its just that every bit helps. Also on the note on giving the planet a moon.... well I never really thought to even bother giving it one. Also if you REALLY want to give the planet a moon or to I don't think it necessarily needs to be as large as our own, whatever works is fine. On the topic of getting asteroids and moving them I think that it may be best to just redirect a few that are on an elliptical orbit that passes within the inner planets. You could probably move the asteroids with probes powered by some electric/and or plasma thrusters (Ion, VASMIR, etc.... Whatever is most suited) or even a NERVA/nuclear engine (We all know we humans have ALOT of spare U-235 among other fun radioactive elements lying around). I'm defiantly not saying this project would be complete in one lifetime or that it would be cheap, but ask yourselves this, How much would you consider another habitable world to be worth to our species?

[Piscator]

How much would you consider another habitable world to be worth to our species?

By the time we're able to move around asteroids routinely, probably not all that much. I think, it's save to assume that engineering will have progressed to a point by then, at which there will be little noticeable difference between living in artificial habitats and living under the open sky. It would probably be easier, cheaper and faster to cover Moon or Mars with bubble domes from pole to pole than terraforming Venus in the described manner. (Assuming that blasting away parts of the atmosphere is a feasible strategy in the first place.)

But since this is supposed to be fun; why not avoid the destabilizing effect on Earth's orbit of moving Venus outwards, by putting both bodies in orbit around each other directly? At the right distance, the tidal effects shouldn't be worse than the moon's (which would have been smacked into Venus at high speeds earlier to change its orbit and speed up its rotation to convenient levels ^^).

[Idobox]

Would it be possible to get rid of the atmosphere by aerobraking asteroids? The way I picture it, you would get asteroids on orbits that get in the atmosphere, but keep enough energy to continue on an escape trajectory. As they plow through the thick atmosphere, they should eject some, especially the stuff in the shock front.

[christok]

Would it be possible to get rid of the atmosphere by aerobraking asteroids? The way I picture it, you would get asteroids on orbits that get in the atmosphere, but keep enough energy to continue on an escape trajectory. As they plow through the thick atmosphere, they should eject some, especially the stuff in the shock front.

An interesting proposal but I don't think so for two reasons.

Firstly, the lighter elements escape preferentially and hydrogen is in very short supply at Venus. The planet has e.g. only ~30 ppm H2O in the higher parts of the atmosphere where it shows up in absorption spectra. (Water is probably less common low down, since it's less dense than CO2.) The crust also seems to be bone dry.

Secondly, you must be at an altitude where aerodynamic effects are significant for the meteors to have the desired effect. So if a random heated molecule wants to escape, it must first go up through a lot of atmosphere interacting with and losing heat to other molecules along the way.

It should cause some loss of gas, but nothing significant compared to what solar radiation and solar wind already does. The gas released by the meteor might even be more for the right kind of meteor (I haven't done any calculations).

[Starwhip]

If you had a big enough asteroid, then yes, some atmosphere would be flung into space. Planet/moon size. Something like Ceres... or Pluto.

[-Velocity-]

By the time we're able to move around asteroids routinely, probably not all that much. I think, it's save to assume that engineering will have progressed to a point by then, at which there will be little noticeable difference between living in artificial habitats and living under the open sky. It would probably be easier, cheaper and faster to cover Moon or Mars with bubble domes from pole to pole than terraforming Venus in the described manner. (Assuming that blasting away parts of the atmosphere is a feasible strategy in the first place.)

But since this is supposed to be fun; why not avoid the destabilizing effect on Earth's orbit of moving Venus outwards, by putting both bodies in orbit around each other directly? At the right distance, the tidal effects shouldn't be worse than the moon's (which would have been smacked into Venus at high speeds earlier to change its orbit and speed up its rotation to convenient levels ^^).

You might have to slam the Moon into Venus at the same time it approaches Earth. That might slow down/speed up Venus enough for Earth and Venus to capture each other...

Considering that this requires just about the power of God, I don't imagine it will ever be done... and I agree that any civilization that would be capable of this probably wouldn't need a planet to live on in the first place. Unless they become so powerful that they do it just because they can...

Edited April 10, 2014 by |Velocity|

[How2FoldSoup]

I feel like I should remind the OP that the AP and PE of the earth is 152 million km and 147 million km respectively. Even more importantly, the 147 million km is during the northern hemisphere's winter. "a meter or a mile" won't change diddly squat for atmospheric changes. Changing its orbit with asteroids would do nothing, even if you could slam that many asteroids into it anyways. Not to mention the higher orbit would defininately mess with Earth's orbit as well and then you have 1 less habitable planet in our solar system. You're better off bioengineering plants that would love Venus's sulfuric acid atmosphere and pump out O2

[*Aqua*]

I think a genetically modified/engineered plant, bacterium or something like that is best. Its only purpose is to chemically bind the sulfur acid and CO2 so it can fall down as 'snow'. This will reduce the thickness of the atmosphere, cooling it down and lessen the pressure.

Still an open question is, where to put all the sulfur and how to bring enough water to the planet.