Venus vs Mars vs Titan

citizen_142002 · 2007-01-10 22:03:25

Titan seems to be the best candidate. Except that it is extremely distant and extremely cold. Technology may someday be capable of mitigating these factors reliably and with a practical amount of effort. I would argue that even though Titan has an atmosphere its temperature and distance make it less likely in the short term than Mars or the cloudtops of Venus.

I'm not sure how long it takes Titan to orbit around Saturn, but there would be a blackout period. Depending on how long the orbital period is that may or may not be a problem.

Does Saturn have a powerful magnetosphere? I had heard that Jupiter's extended all the way to Sturn. Will radiation shielding be necessary?

A question I have forgotten to pose regarding Mars: Does the lack of a magnetosphere on Mars mean that inhabitants would be exposed to unhealthy amounts of cosmic radiation.

karov · 2007-01-12 17:16:56

Titan is the best candidate - yes. It is not extremely cold - the solar radiation intensity / solar factor is only 10 times lower than at Earth. It is not extremely distant - the distances in space must be estimated in delta_v , not in kilometers. The other advantage that to arrive on Titan we have several gravity assist sources ( the Earth, Venus, Jupiter..) and TWO aerobraking bodies in-system: Saturn and Titan itself. Titan is much more accesible than the bigger planets: low escape velocity ( only 7 km/s to leave Saturnian system, not only Titan ), dense cold atmosphere - good spot to deploy supeconductive space fountains, orbital rings, loops... Very important feature is that on TItan the members of a eventual manned expedition in principle can not die - natural cryopreservation

Titan orbitis Saturn for about two weeks. No regular shadings. No problem even if the blackout was once a orbit...\

Saturns magnetosphere: http://www-ssc.igpp.ucla.edu/personnel/ … t_mag.html -- just perfect!!! axicentric - it actualy keeps the titanian atmosphere in place , than like Jupiter to sweep it out via the generated from the excentric magfield radiation "winds".

NO , a repeat NO radiatioon shielding necessary. Titan is one of the most benign in radiation aspect environment which we know: perfect combination of good saturn`s magfield, thick titanian atmosphere...

and, yes on Mars the cosmic radiation is only halved compared with the open space one... the only shieldingis provided from bellow.

cjchandler · 2007-02-14 14:19:56

Wow what a facinating thread! I had no idea venus was so habitable. I have a few questions though, Carbon, Hydrogen, Nitrogen, and Oxygen don't seem to be horribly rare in the solar system, but how about other elements that humans need for industrial processes like halogens and other non-metals? Can these be found on say titan, venus, or on near earth objects?

Tom Kalbfus · 2007-02-20 09:13:44

The thing about Venus is that even if you could live there, the trip would be one-way, its gravity is nearly equal to Earth, so the cost of getting off of it would be nearly the same as getting off Earth. So any astronauts you send to live in the Areostats floating in Venus would be there for the rest of their lives unless rocket technology improves tremendously. If your going to have a manned presence around Venus, they might as well be in orbit, and they can control remote probes on the Surface and in the atmosphere. Venus is a waste or real estate unfortunately. Something may be done about it, but it would take a long time.

The problem with Veus is that its too close to the Sun. I recently read an article about a proposed gravity tug to divert an asteroid from hitting the Earth in 2030-something. A gravity tug would work on Venus also. The same mechanism used which dragged those extrasolar gas giants toward their stars might also be used to drag Venus away artificially. If you have a massive commet or asteroid make a close pass in front of Venus, the gravity will bend the path of that object toward Venus and pull Venus towards it. There would also be a tidal effect involved as the asteroid would pull on the nearest part of Venus more than more distant parts. It might be a good idea to park a number of massive asteroids in Orbit around Venus. The tidal effects would lower the asteroids in their orbits and also speed up Venus's rotation. The same effect might also be had by flinging the same asteroids and comets at Venus or extracting comets from the Kuiper belt and flinging them at Venus to be deflected in front of the planet by that planet's gravity. I think increasing the distance from the Sun to 140,000,000 km would be enough. The minimum distance of Earth is 147,085,800. We don't want the two planets getting too close!

nickname · 2007-02-20 11:33:40

Tom Kalbfus,

That is an interesting idea.
Any guess at how long it would take to move Venus?
And how close to earths orbit before we start tugging on each other?

On the same sort of thought, couldn't we park a large asteroid or KB in a sloppy orbit of Mars to heat its core up?
Maybe mine the asteroid or KB at the same time its in orbit for super greenhouse gasses/water/co2/hydrogen/nitrogen etc for Mars.

Similar to the Io internal heating from its gravitational tugs in the outer solar system.

Tom Kalbfus · 2007-02-20 12:41:49

Probably a long time, it could be done within one million years, maybe less time. Optimistically it could take one thousand years. I think the easiest things to leverage would be oort cloud comets followed by Kuiper belt comets. If you change massive cometary bodies slightly, they would fall toward the Sun, and if you aim them right and anticipate where Venus is going to be, you might arrange for thousands and thousands of comets to approach Venus and swing in front of Venus all at once. Most of the time spent will be in waiting for the comets to fall in toward the Sun, by carefully arranging the velocities of each of these objects, they'll all converge on Venus within a short space of time, but it can take thousands of years to move each cometary body. You can leverage resources and energy with time. If we bent our resources to it, we could probably send a spacecraft out to the Kuiper belt and stop a cometary body in its orbit. The further out the comet is, the easier it is to do, but it takes a long time to get there, it takes a long time for the comet to fall to the Sun, and getting its trajectory just right means anticipating the positions of all the planets tousands of years in advance.

So one by one we change the orbital velocities of thousands of comets, it will seem like a wasted effort by those people who do that. And then thousands of years hences a swarm of comets will converge on Venus, there paths will converge, and thousands and thousands of massive comets fall towards Venus with their long cometary tails, some will impact with the planet while most will miss. The comets travel in front of the planet in the direction of the planets rotation, tidal forces caused by the debris will cause the planet to rotate a little faster with the passing of each comet, and the comets will make close passes to the planet for centuries on end, and afterwards the comets will head out of the Solar System, probably better if they were at escape velocity, as otherwise the comets would head back into the Solar System thousands of years later and threaten Earth. If one stood out at night in that particular era, one would see a spectacular sight, a continuous stream of comets heading in and out of the Solar System, for centuries this would happen. Venus would slowly move outwards from the Sun, widening its orbit and sinning faster, until it appeared just inside Earth orbit by a few million kilometers. Probably by this time enough comets will have impacted with Venus so as to give it sizable oceans, and on its way outwards, life will have been established on the planets surface and oceans. With the increased spin, Venus will have developed a magnetic field, also in the process we can add a tilt to the planet so that it has seasons. This kind of effort would require a civilizational commitment for a very long time.

RickSmith · 2007-03-03 02:17:14

Titan is the best candidate - yes. It is not extremely cold - the solar radiation intensity / solar factor is only 10 times lower than at Earth.

Hi Everyone, Karov.
According to my book the Semi-major axis for Saturn is 9.539 AU. The insolation is an inverse square law so I calculate that the solar radiation is 1 / 90.99 times that on Earth.

Beyond the Asteriod belt, the light from the sun starts getting too low for plants. We will need artificial light for our gardens on Titan and that will require a LOT of energy. (Of course if they have He3 mining of the outer solar system then people will have energy to burn...)

Warm regards, Rick

RickSmith · 2007-03-03 02:25:39

The problem with Veus is that its too close to the Sun. .... . I think increasing the distance from the Sun to 140,000,000 km would be enough. The minimum distance of Earth is 147,085,800. We don't want the two planets getting too close!

Hi all, Tom.

When Venus got to be 112,500,000 km from the sun it would be in a 4:3 resonance with Earth and then it would start having STRONG effects on Earth's orbit.

Also this would require a gigantic restructuring of the solar system to move that much mass. For example, the oort cloud starts around 50,000 AU. They orbit at a speed of 0.1 km / s relative to the sun. This does not sound too bad, we only have to give them a 100 m/s delta vee and the Sun's gravity will do all the rest. However, it will take this comet 60,000 years to fall into the inner solar system from that distance (1/2 of the typical orbital period for comet thought to be coming from that part of the oort belt.)

I estimate that you will want to give the comets a mid course correction of around 5 m / s in 55,000 years to make sure that they miss Earth and go to the right area of the solar system. Spend another 5 m / s over the next 5,000 years to guide the comet where you want it.

Now you are talking momentum transfer here via gravity. From this site:

http://www.egglescliffe.org.uk/physics/ … sling.html

it shows that the comet, AT BEST, can gain double the velocity of Venus (added to its own velocity). Venus is traveling at about 17.5 km/s around the sun so the comet gains 35.1 km/s delta vee.

If the comet masses a trillion kg (a pretty small comet) this is a momentum transfer of 3.51 x 10 ^ 16 kg m/s. That sounds pretty good and is the momentum transfer equivalent to 10,300 Saturn V rockets.

Now to move Venus up to 140 M km will require increasing its orbital velocity to about 28 km / s. This is a momentum change of: 5.1 x 10 ^ 28 kg m / s. This is 1.5 trillion such comets.

Now if you want to get out to the near oort cloud, you can get there in about 60,000 years with a delta vee of 40 km / s. If you want to get there faster, you need a LOT more detal vee. I am assuming that these comets each want a delta vee of 100 m/s to move them into the inner solar system. This is about 29,550 Saturn V's worth of momentum. (Of course you have to move those 29,550 rockets from Earth to each of those 1.5 trillion comets.)

When you have done this you have the heaviest cometary bombardment of the inner solar system, from any time in the history of the sun, only 55 millenia away.

Now you may suggest that in a few hundred years we may have fusion drives and the like, but my point is that planets are big. Really big. I am sorry to say that I think your plan to move Venus is impractical.

I am not trying to make fun of you Tom. Your idea is perfectly possible in principle. However, on a realistic basic, it just won't happen. For that much energy, it is a lot cheaper to go to other solar systems and find worlds that are easier to terraform than Venus.

Sorry to be such a wet blanket.

Warm regards, Rick.

Tom Kalbfus · 2007-03-03 15:45:07

When Venus got to be 112,500,000 km from the sun it would be in a 4:3 resonance with Earth and then it would start having STRONG effects on Earth's orbit.

So every fourth orbit of Venus and every third orbit of Earth, Venus will be pulled outward and Earth inward in the same location in the Solar System with respect to the Sun. What this will do I think is deform the orbits of both Venus and Earth so that they are both more elliptical, once this happens sufficiently, they will no longer be in a 4:3 resonance with each other. So the trick it seems to me is to get Venus past this point and use more comets to recircularize each planet's orbit as we move Venus further out. I don't think 112,500,000 km is far enough out anyway as it is not much farther out than it is now. We probably want something more like 140,000,000 km, something far enough away so that the sun doesn't trigger a runaway greenhouse effect, and so that we don't have to permanently place an object between the Sun and Venus to reduce the amount of light reaching the planet. The Sun is getting brighter, so we might eventually want to move the Earth farther out anyway, though messing with a perfectly ok global climate is a dangerous thing.

Also this would require a gigantic restructuring of the solar system to move that much mass. For example, the oort cloud starts around 50,000 AU. They orbit at a speed of 0.1 km / s relative to the sun. This does not sound too bad, we only have to give them a 100 m/s delta vee and the Sun's gravity will do all the rest. However, it will take this comet 60,000 years to fall into the inner solar system from that distance (1/2 of the typical orbital period for comet thought to be coming from that part of the oort belt.)

One needs to ask, do we have a better use for the Oort cloud comets? As they are, they present a long term danger to the Earth as many of them may be perturbed by a passing star and some of them may impact the Earth. I think getting rid of them may be a good thing as there would then be nothing to perturb when next a star passes close by. Also it may take 60,000 years for the comets to fall toward's Venus, but would it take 60,000 years to alter their orbits so that they do so? How long would our civilizational attention span need to be to set this all up? Undoubtably, we'd have to rely heavily on automation to get this done.

Perhaps something could sit on each comet's surface and give mid course corrections when needed. 60,000 years is about the time it would take to reach the nearest stars with current rocket technology. Interstellar travel, it seems requires lots of patience, and so too does terraforming. I think we may terraform Venus a little quicker by interposing some object between the Sun and Venus at the L1 point, but this would have to be maintained by an active situation. Physically moving Venus could terraform the planet for a billion years, and moving Earth could extend the habitability duration of Earth to account for the increasing solar output as the Sun ages. As things stand now, the Sun has 5 billion years of main sequence life to it, but the Earth will be much like Venus is now, before the Sun goes into Red Giant Stage, if nothing is done to move it further out to compensate.

Now you may suggest that in a few hundred years we may have fusion drives and the like, but my point is that planets are big. Really big. I am sorry to say that I think your plan to move Venus is impractical.
I am not trying to make fun of you Tom. Your idea is perfectly possible in principle. However, on a realistic basic, it just won't happen. For that much energy, it is a lot cheaper to go to other solar systems and find worlds that are easier to terraform than Venus.
Sorry to be such a wet blanket.

All these projects would exceed my natural life, including interstellar travel anyway, unless major advances in medical technology or interstellar propulsion were to occur soon. The future is the future, if its 1,000 years or 60,000 years, it hardly makes any difference to me, but I can still talk about it and make pleasant coversations to pass the time

I think if we travel interstellar distances, we will have to terraform planets anyway. Even an "Earthlike" planet is not likely to be Earthlike enough for us to live on its surface unassistated. To have a truly "second" or "third Earth", we are going to have to make them, in the meantime we will live under domes or in artificial colonies made out of asteroids. Since this will be the case, it will make little difference whether we orbit this star or that star. I think a determined and long lived interstellar civilization can fill the galaxy full of Earth-like worlds, where ever one can exist with enough persistance. The best kind of planet to start out with would be one with all the gross features of Earth, the right rotation rate, the right distance from the Sun, enough water, and an atmosphere that can be easily converted to a breathable mixture due to the addition of the right kind of plant life. We should not have to move planetary masses to get this accomplished, but rather we would have to scour the galaxy to find the right type of planets to easily terraform, simply by introducing the right sort of life to it.

Venus is a special case, as it is in our own solar system, right near the center of human civilization. I think we would be willing to expend greater resources to terraform that planet than some distant extra-solar planet that is light years away. the greatest uncertainty is the longevity of human civilization or the human species. Will we last long enough to see the terraforming project through or at least set things in motion so that they no longer require our active participation to see it through to completion? I think if we dump enough water on Venus and let the comets fly so that they alter Venus's orbit, in due course Venus will cool down and life will appear on its surface.

Mars will definitely be easier to terraform, in the end though the lower gravity environment will leave a significantly alien planet with life on it. If not maintained, Mars will likely lose its atmosphere again and revert to the same state that we found it. If Venus is terraformed and moved, it could last a billion years and have a billion years of life and evolution on it.

RickSmith · 2007-03-03 16:05:50

.... The Sun is getting brighter, so we might eventually want to move the Earth farther out anyway, though messing with a perfectly ok global climate is a dangerous thing. ...
... Mars will definitely be easier to terraform, in the end though the lower gravity environment will leave a significantly alien planet with life on it. If not maintained, Mars will likely lose its atmosphere again and revert to the same state that we found it. If Venus is terraformed and moved, it could last a billion years and have a billion years of life and evolution on it.

It is (my estimate) 12 orders of magnitude easier to top up Mars' atmosphere every 500 million years than to move Venus out to 140,000,000 km so I don't think that, "Mars leaking air", is a valid objection. Also, Earth now has a highly eccentric orbit as we move Venus thru the 3:4, 4:5, etc. resonance points. Is 10,000,000 km far enough apart now?

In the book "The Life and Death of the Planet Earth: How the New Science of Astrobiology Charts the Ultimate Fate of Our World" by Peter D. Ward and Donald Brownlee, argue that in 800 million years the warming sun will render the Earth uninhabitable.

I doubt we will be able to enjoy a billion years life on Venus even if it was moved out to 140,000,000 km from the sun.

Warm regards, Rick

Tom Kalbfus · 2007-03-04 08:29:34

The Earth can be moved further out too, and Venus can be moved to where Earth is now, that way Venus would last 800 million years and the Earth perhaps a bit longer than that. Since the Sun is getting brighter, it must have been dimmer in the past, but despite that there were some warm periods in Earth's past, times when Earth was warmer than it is now.

The Sun is going to last another 5 billion years, but if nothing is done about the Earth's orbit, life will only last 800 million, that means 4.2 billion years of the Sun's light will fall on a lifeless Earth, and I think that is a waste. Something will have to be done about the Earth's orbit if we are to prolong life on this planet, and so long as we are moving planets, why not move Venus as well?

Also what would you propose doing with the planet Venus? Do you propose just pretending that its not there? I think Venus is a waste of a planet, and something ought to be done eventually to put it to good use.

RickSmith · 2007-03-04 13:51:05

Hi Tom.
I think we have to agree to disagree. Did you read how many Saturn V's you would have to send to the oort cloud to make this happen? Do you want to convert all of Earth into rocket fuel in order to avoid wasting Venus?

If you want to move Earth too, well the Earth is heavier than Venus.

It might be easier for you to siphon off 5% of the sun's mass. Both worlds would automatically move into higher orbits and the sun would cool down. That might be enough for Venus to terraformable.

If you postulate that we have a robust He3 economy and antimatter drives, then we will be able to go to other stars in about 55 years. (See "Entering Space: Creating a Spacefaring Civilization" by Robert Zubrin.)

I suspect that the universe has a generous number of worlds that are easier to terraform than Venus.

Warm regards, Rick.

Tom Kalbfus · 2007-03-05 09:56:52

Hi Tom.
I think we have to agree to disagree. Did you read how many Saturn V's you would have to send to the oort cloud to make this happen? Do you want to convert all of Earth into rocket fuel in order to avoid wasting Venus?

If you assume we would use chemical rockets such as the Saturn V, but that is a ridiculous assumption. I've also heard that if we use chemical rockets to travel to the nearest stars, the stages required would outweigh all the matter in the Universe, that say to me that we won't be using chemical rockets for interstellar travel. Also the planet that's made out of rocket fuel is Jupiter, but the comets come with their own rocket fuel. Any civilization capable of moving planets, won't be using chemical rockets anymore.

If you want to move Earth too, well the Earth is heavier than Venus.
It might be easier for you to siphon off 5% of the sun's mass. Both worlds would automatically move into higher orbits and the sun would cool down. That might be enough for Venus to terraformable.

That would come at the expense of Mars though. I don't think we are at the final "end of Days" stage of technology and that it will be the 20th century for the next 10,000 years, I think we'll end up with more efficient rockets than Saturn Vs, what those rockets will be is hard to say, there are several likely candidates of course. The requirements for moving planets within the solar system is in someways less strenuous than interestellar travel. High relatavistic speeds aren't required for instance. Terraforming will be more like gardening at this late stage in human history. Mars will no doubt be terraformed first, and its probably easier to build a free space colony than to terraform a planet, but people will eventually look at Venus and say, "Wouldn't it be nice if we had a second Earth? Sure there are plenty of more likely candidates in other star systems, but we live here, and also Earth is here. It is more easier to transfer life from Earth to Venus than from Earth to som eplanet orbiting some distant star. Also we can apply the resources of a Solar System spanning civilization toward moving Venus, while around some distant star we only have the resources of a star ship and its crew.

If you postulate that we have a robust He3 economy and antimatter drives, then we will be able to go to other stars in about 55 years. (See "Entering Space: Creating a Spacefaring Civilization" by Robert Zubrin.)
I suspect that the universe has a generous number of worlds that are easier to terraform than Venus.
Warm regards, Rick.

Yes, we will terraform plenty of Worlds, some will be terraformed because they are easy to terraform, while others will command the resources of a Type II Civilization because of its close proximity to human civilization, that's all I'm saying. People will value a second or third Earth more that the trillions of comets orbiting the Sun. There are plenty of things we might more easily do than terraform Venus, and we shall do them. I think in the Long Run, all four planets might be moved to within the habitable zone. Probably the first step would be to shade the planets since that is easier than moving them. Venus could be terraformed longe before it is moved to the proper orbit. An easier thing to do would be to spin up Venus, hitting Venus with comets on sideways trajectories in the same direction will increase its rate of spin and add volitiles.

samy · 2007-03-08 17:37:11

Personally I think messing around with Venus' orbit isn't something we should do...next thing we'll know, we'll have sent the Earth spiralling into the Sun...the slightest miscalculation in moving Earth's nearest planetary neighbor could have DISASTROUS results. It's a risk I'd rather not take. Venus can be terraformed without moving it anyway, so I don't see a lot of added benefit to messing around with its orbit.

Tom Kalbfus · 2007-03-09 08:55:14

Personally I think messing around with Venus' orbit isn't something we should do...next thing we'll know, we'll have sent the Earth spiralling into the Sun...the slightest miscalculation in moving Earth's nearest planetary neighbor could have DISASTROUS results. It's a risk I'd rather not take. Venus can be terraformed without moving it anyway, so I don't see a lot of added benefit to messing around with its orbit.

You don't realize how difficult it is to send something into the Sun. NASA has plans to send a probe toward Mercury, and it requires multiple gravitational assists. Any shift in Venus's orbit will occur gradually. Rick Smith seems to think this is not worth doing because it will take a long time and eat up so many resources, I agree with the first part, but I come to a different conclusion.

Yes Venus can be terraformed right where it is, but to make the terraforming long last, the planet needs to be brought further away from the Sun. I believe a civilization should stand on its monuments, and no civilization lasts forever. Maintaining the apparatus that shields Venus from the Sun requires a perpetual civilizational attention, once that civilization goes away, Venus reverts to her former self; if we brought Venus further out, then the planet will reach a life sustaining equilibrium rather than rely on an artificial shield between itself and the Sun. The L1 point is extremely unstable by the way, and that's where the parasol will have to be stationed, the slightest push, if not corrected for will remove the shield and expose Venus to the harsh rays of the Sun. It could be as simple as a slight varience in the Solar Output. If the Sun increases in brightness for example, that Sunlight will push the parasol harder towards Venus and out of the L1 point, Venus's gravity would then pull it further away either into an elliptical orbit around Venus or into a different orbit around the Sun. The Parasol needs self-correcting mechanisms to keep it at the L1 point and those mechanism need to be maintained over time by an active civilization, or else it will fail and the Parasol will drift.

samy · 2007-03-09 11:48:07

Yes Venus can be terraformed right where it is, but to make the terraforming long last, the planet needs to be brought further away from the Sun.

Not that I'm aware of. It can be terraformed perfectly fine where it is. If you want to reduce the solar constant, a solar shade makes FAR more sense, as it is a LOT less work, than moving around a planet-size mass for 0.3 AU.

The Parasol needs self-correcting mechanisms to keep it at the L1 point and those mechanism need to be maintained over time by an active civilization, or else it will fail and the Parasol will drift.

If we don't have an active civilization on Earth or Venus, we've got worse problems than maintaining Venus' temperature.

Tom Kalbfus · 2007-03-10 04:30:01

Not that I'm aware of. It can be terraformed perfectly fine where it is. If you want to reduce the solar constant, a solar shade makes FAR more sense, as it is a LOT less work, than moving around a planet-size mass for 0.3 AU.

Venus is the way it is because it is too close to the Sun, that means Venus would have to be permanenly shaded if an Earthlike environment is to be maintained.

If we don't have an active civilization on Earth or Venus, we've got worse problems than maintaining Venus' temperature.

What civilization has lasted millions of years? I can't think of any. Earth had life for millions of years, and their was no intelligent civilization to help maintain it, the Earth maintained itself. A living ecosystem on Venus needs to be continously propped up by intelligent forces. History suggests that no civilization lasts forever, they all have their rise and fall, most last less than a millenium. A terraformed Venus would be the equivalent of the Egyptian pyramids, a monument that outlasts the civilization which built it. You are indeed an optimist if you expect human civilization to go on until the Sun leaves the main sequence.

nickname · 2007-03-12 07:14:42

I see lots of people with ideas for Venus involving sun shades, but the size and stability of such a structure in space with solar winds/storms so strong near Venus eludes me.

The only way i can convincingly make a sunshade at Venus is to collide small asteroids in orbit creating a debris ring.
Even that will only create about 25% shade, probably not enough to cool things enough to start doing anything useful on the surface.

The mass of carbon at Venus also has its possibilities as a smog debris ring orbiting Venus.
Problem with that is getting it to orbit.

Just my opinion, but i don't think Venus will be seeing a useful sunshade approach as a way to cool things to begin a terra form.

samy · 2007-03-12 07:30:50

Just my opinion, but i don't think Venus will be seeing a useful sunshade approach as a way to cool things to begin a terra form.

I don't think it's terribly viable either, but it's orders of magnitude more viable than MOVING THE PLANET.

nickname · 2007-03-12 09:05:02

samy,

Yeah just the thought of the large sloppy orbit object needed to move Venus over 10,000 years gives me shivers.
One bad impact day or very sloppy orbit day at Venus probably would be a bad day for earth later on.

Even if you could move Venus somewhat easily, i would think that the delicate balance of moon earth would be impacted if Venus was much closer than it is.
Just a tiny extra tug more on the moon than on earth with each orbit would cause some serious problems on earth.

The sunshade for Venus is such a good idea in theory, but in practice it seems near impossible.
Probably better to think of Venus as a carbon and o2 bank, then change Venus with co2 withdrawals over many thousands of years when we need recourses.

Tom Kalbfus · 2007-03-12 09:22:29

samy,
Yeah just the thought of the large sloppy orbit object needed to move Venus over 10,000 years gives me shivers.
One bad impact day or very sloppy orbit day at Venus probably would be a bad day for earth later on.
Even if you could move Venus somewhat easily, i would think that the delicate balance of moon earth would be impacted if Venus was much closer than it is.
Just a tiny extra tug more on the moon than on earth with each orbit would cause some serious problems on earth.
The sunshade for Venus is such a good idea in theory, but in practice it seems near impossible.
Probably better to think of Venus as a carbon and o2 bank, then change Venus with co2 withdrawals over many thousands of years when we need recourses.

There is another way to move Venus without comet flybys.
You could build a giant fusion space ship or a fleet of fusion space ship, and have them lead Venus ahead in its orbit, they would have fusion torch engines which produce just enough thrust to keep the gravity of Venus from pulling them closer, the engine exhausts would be aimed so as to miss Venus entirely, the engine nozzils would be vectored to produce a net thrust directly away from Venus in the direction of its orbit while the exhaust streams would diverge so they just miss the planet and continue on past at escape velocity. A steady supply line of tanker space ships would make the circuit between Saturn and the spaceships keeping them fueled at all times. The rockets simply over there against Venus's gravity.

Venus's gravity exerts a pull on the rockets, and thus obeying Newton's law of motion the rockets exert an equal pull on the planet, and since the exhaust stream misses the planet, there is a net pull on Venus in the direction of its orbit. Over time Venus' orbit will get wider and wider as the planet moves further from the sun. In the meantime a few comets impact with Venus, both adding spin and volitiles. Dust kicks up in the atmosphere reducing the sunlight that reaches the surface and thus cooling it. This process does a number of things, cool the planet, spin it up and also move it further away from the Sun. Since the comets impact with Venus, they are not still around to bother the Earth. The impacts will be timed so they don't heat up the planet so much due to their frequency, the dust should stay up in the atmosphere, creating nuclear winter like conditions, and when the dust settles another comet hits.

dicktice · 2007-03-12 17:56:15

The delightful alternative means of "populating Venus" using bouyant cities floating in the atmosphere just beneath the clouds, springs to mind.

nickname · 2007-03-12 18:35:21

Tom Kalbfus,

Interesting idea.
Couldn't we just separate the co2 on Venus into C and o2 an excellent rocket fuel.
Find a good use for the C in the project and you have a decreasing atmosphere while you are moving the planet.

Solar power for separation and power to get both o2 and C into orbit.
60 something bars of liquid oxygen would be some heavy duty thrust.

dicktice,

I think your idea of the floating cities will be the only way we will settle Venus.
Might also be a great long term production facility in the longer teraform terms.
I still don't like the acid clouds that are sure to make materials a problem.

SpaceNut · 2007-03-17 19:54:56

We may need to think of other mixes of gasses that still would be ok while we try to teraform Mars. One main issue for resolution is in the air we breath which as much as we would like mars to be will probably never be like Earths. So what mixed gases can we breath and stay heathly?
Martian Air Breathing Mice and crickets in sealed environments while pumping through a breathing mixture of 40% argon, 40% nitrogen and 20% oxygen.

Tom Kalbfus · 2007-03-17 21:11:28

But the initial ratio of Nitrogen to Argon is not 1:1, so making it so would invovle seperating of gases, which is what is difficult. Argon is a nobel gas, much like Helium but heavier, thus it reacts with nothing. Is it radioactive though?

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