Collisional planetary engineering - bomb Venus with 1388 Kleopatra

karov · 2005-04-14 14:28:16

About 4.6 bln years ago the Earth collided/merged with Mars-size body, dubbed by the theorists Theia ( http://en.wikipedia.org/wiki/Theia_%28p … 8planet%29 ). The splashed out by the impact debris in about months or days coalesced to form the Moon. Cause the upper parts of the Earth were orbited by the hit - this explaines why the Moon is so devoted of heavy elements, and why the Earth has so thin crust, enabling tectonics, hence long run chemical cycling thermostat... Why not repeat this with Venus? - brouse the older posts of mine about Venus terraforming in this forum, where I point figures that about 15 times more water than the surface hydrosphere resede in the upper Earth mantle. The same should be with Venus - the planet lost long time ago its surface ocean, but the mantle reservoir must be still in place sealed in the planet... Induced specific impact should release sufficient amount of it.

http://en.wikipedia.org/wiki/Giant_impa … act_theory
http://www.psi.edu/projects/moon/moon.h … /moon.html
http://www.space.com/scienceastronomy/s … ...-1.html

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So, Theia was Mars-mass and hit Proto-earth with about the minimal collision velocity of 11.2 km/s -- say, 10 000 m/s for convenience... ( minimal cause the earth is still in the inertial frame, Theia comes as a co-orbiter from the Earth-Sun L4 or L5 point...). Theia having almost equal to the Martian mass of 6.5exp23 kg, is about 2exp5 times more massive than the asteroid 216 Kleopatra - M class iron nikel with very good projectile form of a "dog bone". So in order to be able to do to Venus the same job as Theia with Earth 4.6 bln years ago, it should hit the planet with ~140 times bigger velocity, or to be accelerated to about 1500 km/s.

1500 km/s seem huge but can be achieved with existing technology of the 1950`es. I`m talking about the nuclear bombs pulse rocket "Orion" . The iron asteroid body is natural "pusher plate". SEveral million multimegaton explosions at one of the ends + gravity assist maneuvre ( firing at the perihelion of say, Jupiter and the SUN - R.Forward style of injection...) would haul Kleopatra to Venus with the necessary speed, hitting it from the direction of the Sun. A glancing hit of this >200 km long steel arrow would penetrate to the core of Venus - totally mixing the mantle, causing massive to comprehencive outgasing of water, stripping most of the CO2 nowaday atmosphere, and splashing enough material to form a moon-size body in orbit around it, and gaining enough angular momentum for a comparable day cycle as Earth. A planet so deadly wounded will not be worse as conditions than nowaday Venus, but it would contain ON the surface all the necessary chemicals and volatiles - mostly the valuable water...
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Indeed I do not recomend such violent way of planetary engineering anywhere within the SolSys, but somewhere out of it, around a lifeless star... Why not?

karov · 2005-04-15 06:00:26

Excuse me , the topic contains a mistake of the number designation of the proposed projectile-asteroid. Actually, not 1388, but http://en.wikipedia.org/wiki/216_Kleopa … _Kleopatra -- 1388 is the asteroid 1388 Aphrodite, not the necessary iron-nikel M-class, but much smaller and softer body, which doesn`t work for the purpose to serve as Giant Moon-forming Impactor for Venus...

216 Kleopatra is the right one. The acceleration of it generally should pass through several major phases:
1. Accelerate it in course of close fly-by with Jupiter
2. Gravity assists acceleration phase during the biggest proximity to the gas giant fly-by maneuvre and heading directly to the Sun.
3. Very close fly-by around the Sun with another momentum injection in order to hit Venus from the Sun-side...

MarsDog · 2005-04-16 16:51:15

Anyone run a computer simulation of such collision ?

http://www.google.com/search?q=collisio … =en&lr=]It seems to be a popular interest.

karov · 2005-04-17 03:10:47

Hi MarsDog,

Lots of simulations. The result is that 4.45 Gyr BeforePresent ( about 50 Myr after the begining of the SolSys)... that should happened. May be the best compact sourse is again the Wiki:

http://en.wikipedia.org/wiki/Giant_impa … act_theory

it includes very simple and usefull animation of the event.
-----------------------------------------

Don`t you think we can recreate the effects: Moon-formation, faster axial rotation, mantle water extraction, etc. with Venus using much less massive projectile/impactor moving with proportionally higher velocity?

chat · 2005-04-17 04:46:55

karov,

I guess its physically possible to collide a large object into Venus and create a moon.

I can think of a lot of reasons why you wouldn't want to do that.

Any large object moving in the inner solar system will perturb all of the inner solar system orbits.

Venus with its 62 bar co2 atmosphere would probably still retain most of that after the moon forming collision.

The wait for the planet to return to a sense of normality will be longer than primates have existed on earth.

It's an interesting idea for some other solar system.

karov · 2005-04-17 06:16:45

karov,
I guess its physically possible to collide a large object into Venus and create a moon.
I can think of a lot of reasons why you wouldn't want to do that.
Any large object moving in the inner solar system will perturb all of the inner solar system orbits.
Venus with its 62 bar co2 atmosphere would probably still retain most of that after the moon forming collision.
The wait for the planet to return to a sense of normality will be longer than primates have existed on earth.
It's an interesting idea for some other solar system.

Yes, it is physicaly possible, and it is technically feasible to redirect iron/nikel asteroid to colide with Venus. We can use solar energy tapping, huge hydrogen bombs, gravity-assist with Jupiter and the Sun in order to make object with mass of the order 10exp18-10exp20 to move with velocity of 0.5-3% of the light speed and to hit Venus under the right angle.

The main reason why we shouldn`t do this here in SolSys is that perhubs about 0.5-1 lunar masses would be scattered in the inner system as NearEarth Asteroids ( the about half of the collision splashed mass which wouldn`t coalesce in venusian moon), increasing the collision threat to unacceptable levels ( although vast array of anti-meteorite defences can deflect even dozens of asteroids heading into collision course a year, given sufficient energy available -- I mean civilization which could move Kleopatra mass with 1500-3000 km/s, can easily sweep several thousands of asteroids per year off earth orbit)...

216 Kleopatra moving with 1500 km/s through the inner system is far too small to cause any noticeable disturbance in the planetary orbits. The question is indeed what change in the VENUSIAN orbit the collision with it will cause, hence secondary deviations to the other bodies` orbits here... A double collision which will not touch the orbit but only will induce increase in the axial rotation, is may be the answer. I can not do the actual calculations, but only to point out the possible consequences...

Venus with its >90 bars of CO2 ( why you constantly post the 60-s.t. number?) will retain most of it atmosphere after such impact, but the trick is that one or two earth-size hydrospheres will be released -- so although the temperature and the mass of the atmosphere will be increased, a problem resolvable not nore difficult than in the original status, BUT this new heavier, and warmer atmosphere will contain WATER, will be wet -- hence all the necesarry for installing brethable atmosphere, hydrosphere, and biosphere will be in place. The shortened day-cycle will allow the use of orbital elevators, to ease the extraction of the excessive amounts of volatiles...

See, http://www.paulbirch.net]www.paulbirch.net ( i think in 'Terraform Venus quickly")
about the possible ways to cool down quickly a planetary layer or even bigger structures. Indeed in matter of decades using megascale processing we could extract the excess of energy in the upper several dozens of km of the venusian crust in very usefull thermal machines way, without to dissipate it -- thus BTW, returning the delta-V/energy investment in the projectile/impactor...

karov · 2005-04-17 06:22:48

...and yes, other stellar systems will be very probably scenes of such collisional/merger/coalescence/splash engineering...
Remember the Oort cloud/ Kuiper disk planetary coalescence which long time ago I proposed? This could be implemened in other places , too. For example -- very yound proto-systems where THOUSANDS of terrestrial planets with dynamicaly supported orbits, could be formed within the habitable zones... Mutual collisions of planets with excentric orbits in some systems for dynamical normalisation... Even total engineering of Bock globules in order to program the future system development in the most valuable way...

Austin Stanley · 2005-04-17 15:10:14

The only conceptual problem I see with this plan is that it would be very hard to impossible to determine what exactly the consiquences of the impact will be untill after the fact. I mean collisions of this velocity haven't happened in the recent history of our system. Indeed 1500km/s is more than double the velocity needed to escape from our solar system so any natural impactor would probably be extrasolar in nature. Also by there very nature these sorts of impacts leave little evidence behind with which we might determine exactly what might have happened, if an impact of this sort had occured previously.

But perhaps in the future it will be possible to predict the consiquences via advanced computer simulation. But I still have my doubts. The consiquences of such an extream impact will probably be impossible to predict untill they actualy happen.

chat · 2005-04-17 17:33:55

karov,

I've read Venus atmosphere to be from 62 bars to 97 bars.
I just take the lower number and run with it.

Venus surface bar pressure is probably somewhere in the middle of those (85 ish).
When i say 85 people tend to say its less, and accuse me of over estimating.

I think you would find on a current Venus that most of the water in the first 10 or more km has been baked off in the first 4.5 billion years.
The hydrogen depletion due to steam in the runaway greenhouse is probably the reason Venus is the way it is now, its something that should be put in any calculation that involves a water based planet after an impactor.

A collision with Venus will produce much less water than the earth/moon forming collision did, and the 85ish bars of pressure even with luck will be 42.5 bars on a hellish lava place that makes the current Venus look nice.

At 600c days and -200c nights on Venus surface i see no way anyone could ever place a birk chimney on the surface even at the crushing 42.5 bars.
Nor any machine that could survive long enough to do anything useful.
The tank like Russian venera lander lasted 43 minutes.

I agree its a useful tool to recreate other solar systems, but the wait will be long for any planet we decide to recreate this way.
With enough energy and resources to move planetoids, we could probably teraform Venus like worlds with similar energy amounts and less wait with less drastic methods.

RobS · 2005-04-17 23:27:32

I can't imagine we'd actually be able to accelerate an asteroid to that kind of speed, but even if we could, I doubt the collision would release water. Venus has volcanism and the volcanism, as I understand it, has dried out its interior. So the Venus crust and mantle don't have any water in them any more. It has escaped to space as well.

If you're talking about an impact the energy of the one that created the moon, the outer tens of kilometers of Venus would be a magma ocean for some millions of years. The heat might indeed drive away a lot of the CO2. But the place wouldn't cool to a useful temperature in any reasonable timeframe.

-- RobS

karov · 2005-04-18 02:00:04

The only conceptual problem I see with this plan is that it would be very hard to impossible to determine what exactly the consiquences of the impact will be untill after the fact. I mean collisions of this velocity haven't happened in the recent history of our system. Indeed 1500km/s is more than double the velocity needed to escape from our solar system so any natural impactor would probably be extrasolar in nature. Also by there very nature these sorts of impacts leave little evidence behind with which we might determine exactly what might have happened, if an impact of this sort had occured previously.
But perhaps in the future it will be possible to predict the consiquences via advanced computer simulation. But I still have my doubts. The consiquences of such an extream impact will probably be impossible to predict untill they actualy happen.

Really huge computer simulation of such impact is possible and if comprehencive enough could predict with great accuracy the consequences.
Naturally such speed of impact is almost surely never happened cause the astronimical bodies of our vicinities move orbitally aropund the galactic center with speeds of around 150-250 km/s. Only asimetric expolsion of supernove is thought to cause the resulting neutron star to be cannon-balled with speeds of the discussed impact range ( 1000 km/s or more), but this is out of assumption cause this invoplves bigger than solar masses, and it is out of any mass range for planetary engineering task...
Actually 1500 km/s are not naturally achievable for any planetoid mass and exceed much more than twice the escape velocity for any SolSys object. The Earth moves around Sun with 30 km/s -- its escape velocity from this orbit is only about 40 km/s...

karov · 2005-04-18 02:21:09

karov,
I've read Venus atmosphere to be from 62 bars to 97 bars.
I just take the lower number and run with it.
Venus surface bar pressure is probably somewhere in the middle of those (85 ish).
When i say 85 people tend to say its less, and accuse me of over estimating.
I think you would find on a current Venus that most of the water in the first 10 or more km has been baked off in the first 4.5 billion years.
The hydrogen depletion due to steam in the runaway greenhouse is probably the reason Venus is the way it is now, its something that should be put in any calculation that involves a water based planet after an impactor.
A collision with Venus will produce much less water than the earth/moon forming collision did, and the 85ish bars of pressure even with luck will be 42.5 bars on a hellish lava place that makes the current Venus look nice.
At 600c days and -200c nights on Venus surface i see no way anyone could ever place a birk chimney on the surface even at the crushing 42.5 bars.
Nor any machine that could survive long enough to do anything useful.
The tank like Russian venera lander lasted 43 minutes.
I agree its a useful tool to recreate other solar systems, but the wait will be long for any planet we decide to recreate this way.
With enough energy and resources to move planetoids, we could probably teraform Venus like worlds with similar energy amounts and less wait with less drastic methods.

Venus facts:
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1. " Venus has an atmosphere consisting mainly of carbon dioxide and a small amount of nitrogen, with a pressure at the surface about 90 times that of Earth (a pressure equivalent to a depth of 1 kilometre under Earth's oceans)"
2. "The solar irradiance is so much lower at the surface of Venus because the planet's thick cloud cover reflects the majority of the sunlight back into space. This prevents most of the sunlight from ever heating the surface. Venus's bolometric albedo is approximately 60%, and its visual light albedo is even greater. Thus, despite being closer to the Sun than Earth, the surface of Venus is not as well heated and even less well lit by the Sun. In the absence of any greenhouse effect, the temperature at the surface of Venus would be quite similar to Earth. A common conceptual misunderstanding regarding Venus is the mistaken belief that its thick cloud cover traps heat, as the opposite is actually true. The cloud cover keeps the planet much cooler than it would be otherwise. The immense quantity of CO2 in the atmosphere is what traps the heat by the greenhouse mechanism."
3."The interior of Venus is probably similar to that of Earth: an iron core about 3000 km in radius, with a molten rocky mantle making up the majority of the planet. Recent results from the Magellan gravity data indicate that Venus's crust is stronger and thicker than had previously been assumed. It is theorized that Venus does not have mobile plate tectonics as Earth does, but instead undergoes massive volcanic upwellings at regular intervals that inundate its surface with fresh lava. Other recent findings suggest that Venus is still volcanically active in isolated geological hotspots"
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from: http://en.wikipedia.org/wiki/Venus_%28p … 8planet%29
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So: The surface pressure is 90-95 bars - tell you friends to not take the pressure estmated for the higher elevations ( mount Maxuel, etc.). It is confirmed absoultely.
The thickness of the crust greater than Earth`s means weaker volcanism - so the interior primordial water and other volatiles content of Venus should be even better preserved than Earth`s one. No tectonics. The thicker venusian crust is well explained by the quoted "BigSplash" moon-formation scenario - on earth the original iron-poor crust was orbited by the impact - the remaining lighter rocky blankets flow over the basaltic magma of the mantle. The resulting tectonics for also the carbo-silicate cycle -- VITAL for the action of the global chemical exchange thermostat - otherwise the CO2 would be either trapped under the surface or totally sedimentized, or would be totally released in the atmosphere like in the venusian case. Thicker Venusian solid crust and lower activity means that the water is better sealed...

Yes, the planet will totaly be melted, but these 4-5 000 000 000 km3 of upper molten lava layer` of ready thermal energy could be utilized/tapped for chemical and transportational processing of the new - wetter and hotter atmosphere into colder and earth-like. The cooling and processing would take no longer time than in the other scenarios, except this that mantle water extraction would spare the terraformers the need to wait decades or centuries the slower outer sistem water-rich bodies to be delivered...

Regard the projectile shear speed! Even if the upper mantle water is fried out... A bullet moving with just 10 km/s, is observed to penetrate about 10 times its own lenght in any target regardless the material of which it is made. A Kleopatra size iron/nikel "arrow" >200 km long with 1500 km/s should penetrate for seconds down to the very core of the planet - thus utterly mixing the interior and expeling all the volatiles out.

Look at: http://www.paulbirch.net/TerraformingVe … uickly.zip --

pages 158, 159

chat · 2005-04-18 05:47:41

karov,

Thanks for the Venus weather report, i will be sure to tell people 90 bars and if they get bitchy i will mention your name.

I've read all about the birch chimney, on paper it seems to work well, the only minor detail that doesn't work is actually placing it or building it on Venus.

When you start to discuss the problems with actually putting the theory into practice on Venus it doesn't work.

A 233 day window is all that exist to build or place the chimney on Venus, then the 600c day arrives and evaporates the chimney.
In that 233 day window machines must deal with -200 c temperatures and 90 bars of pressure.

To build a chimney on Venus it would require about 275 days plus all the infrastructure on the surface to build it.

To land one pre built on Venus it will require about 14 billion pounds of thrust to land it and launch it and the infrastructure to make it.

The option to build a moving chimney that stays on or near the night side will require an additional 100 days to build.

IMO the chimney idea works but only on paper.
The general idea of the chimney is good, but the building is not feasible.

Building one is not necessary anyway as a similar chimney system can be made from space with no structure on the surface.

As we discussed in particle beam/lens/xray heating of local areas to do the same thing on an earlier set of posts.

karov · 2005-04-18 09:35:15

As you may be noticed - NO temperatural difference and change on the surface of Venus with the latitude or day/night! Hence we have to deal only with the constant about 500 degrees celsius. :-) In case of moon-forming scale impact the surface temperature will be close to these 1000-1200 degrees centigrade of the molten rock atmospheric bottom, the massive degasation of the venusian interior will eventually double or triple the atmospheric pressure, hence the shear hight of the air column to >100 km. THere in the hights the temperature as usual will be tolerable by human standarts, not to speack about machines. Pinting the P.Birch`s sourse, I don`t mean the brick chimney design , but indeed the opportunity to use much more effective heat exchanger stuff, which to forceably move around Venus...

Remember the foamed glass bubbles filled with water -- with which runned around, Birch proposed the supraSol layers to be cooled -- the scheme is exact replica of any home refrigerator which moves heat from colder place to warmer MECHANICALLY... Using orbital rings at Venus, with downer sections dipped in the not so hot atmosphere layers, we could not only extyract the heat but to harness it to move the machinery, to export the excessive gases, etc. If you are able to pass all the heat of these about 5 000 000 000 000 000 000 tonnes of molten rock from the uppermost 10 miles from 1200-1500 K to the normal 300 K... through cosmic heat sink of 3 K... This is lots of energy - it will take me a little time, so I`ll post you later the specific numbers.
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BUt, lets go back to the theme: My oppinion is that hiting Venus with Theia/Mars-like amount of kinethic energy via accelerated iron asteroid for projectile, under very carefully chosen and calculated anlge of impact, we simultaneoisly ( AT ONCE) will achieve, several advantageous features belonging now to EArth, and if regarded desirable ( and they are) - achievable with numerous time-consuming complicted worse methods... These features are:
1. Normal diurnal cycle lenght - dozens of hours;
2. A big Moon - to drive tides ( this could be very usefull for the shallow ocean areas where on earth the majority of the bioactivity and chemical exchange is held) and BTW, second object for terraforming;
3. Thinner crust and tectonics ( for the carbo-silicaste thermostat cycle);
4. Extracting the mantle water out on surface...

karov · 2005-04-18 13:25:13

If we use other bodies with shown mass the following figures apply to compensate with impact speed the insufficient to Mars-equivalent mass:
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16 Psyche - 1.7*10exp19 kg, should hit with 2000 km/s
4 Vesta - 2.7*10exp20 kg, should hit with 500 km/s
1 Ceres - 10exp21 kg, should hit with only 250 km/s

BTW, it comes that perhubs using 4 Vesta will be more reaction mass efficient. In order to haul the 15 times lighter 16 Psyche to 4 times higher speed , you`d need 16 times bigger energy / reaction mass proportionaly...

The champion is of course 1 Ceres - with 1 / 640th the Martian ( i.e. Theian ) mass the biggest planetoid in the Inner SolSys will do the job if accelerated to only 250 km/s yielding the energy as a full martian mass colides with Venus with ~10 km/s...

The acceleration: it seems not so difficult, not technological but problem of scale of production and supply. Lets quit the "Orion-style" nuclear bomb pulse rocket -- it is not good for such soft and such heavy body. Instead use huge array of arc-jet rockets + el.mag.accelerators to evaporate, ionize and haul to 10 000 km/s only several %s of the 1 Ceres mass, no mater what kind of material you "burn" as a reaction mass. We can still use the gravitational slingshot maneuvre passing close to the Sun.
The energy sourse - cover the whole body with MW rectenae array ( also serving as parasol in order to not lose mass passinmg near to the Sun.), and pour it with all the necessary 5*10exp32 Watts... which is only about the total solar output for 1 000 000 seconds... or via tapping for ~100 years the energy output from 1 / 1000th of the solar output...

You play, I`m tired.

chat · 2005-04-18 17:52:20

karov,

Sorry badly typed post on temperature.
600c +- 200c.

600c day side 400c night side.

I agree with your thinking that cooling Venus is not necessarily the best way to teraform Venus.

As you point out we only need to heat Venus another 400 c or so to have co2 escape.

But do we need to heat all of Venus to escape co2?
Or just a small local area of a few km's heated to 1000c-1200c to have the same effect.

Maybe just 10 large focal lenses all pointed at the surface in geo orbit of Venus will do that.
The only power requirements for that is to make the lenses get them to Venus and keep them in geo.

I've always been an advocate of heating Venus to make it more tolerable, or at least make it tolerable for machines on the surface that can survive to continue the teraform.

Collisions with Venus are a great tool for heating Venus, but at a price of recovery time after the collision.

I don't doubt that we could collide anything with Venus, but the recovery wait might be longer than humanity exists.
Small collisions might prove to be a useful tool on Venus, and large ones on solar systems other than ours.

I'm always willing to play, but why is venus such a painful #@$@%@% opponent.

Austin Stanley · 2005-04-18 20:23:30

You hit on my point exactly, any natural impact of this sort would have to be from a source outside our solar system, and thusly given these sizes and the distances invovled, incredibly rare. (BTW I was refering to the escape velocity very close to the sun's surface ~600km/s about as fast as you can go and still remain within the solar system.

Problems with prediction of the results are my only issue though. Extensive study of the inner geology of Venus (very hard to do), would certianly be necessary and even then I am dubious. And I agree that it should be possible to accelerate an M type asteroid to the necessary velocity to the Orion method.

As Venus terraforming methods go, I don't think this one is half bad. Even if you only increase the rotation velocity and blow off some of the CO2 atmosphere, it would be worth it. Although I agree it would still be a long term proposal as you wouldn't want to be on the surface for quite a while. Another problem might be the release of other undesirable chemicals, along with H20, especialy sulfur, which venus already has to much off.

karov · 2005-04-19 03:38:20

You hit on my point exactly, any natural impact of this sort would have to be from a source outside our solar system, and thusly given these sizes and the distances invovled, incredibly rare. (BTW I was refering to the escape velocity very close to the sun's surface ~600km/s about as fast as you can go and still remain within the solar system.
Problems with prediction of the results are my only issue though. Extensive study of the inner geology of Venus (very hard to do), would certianly be necessary and even then I am dubious. And I agree that it should be possible to accelerate an M type asteroid to the necessary velocity to the Orion method.
As Venus terraforming methods go, I don't think this one is half bad. Even if you only increase the rotation velocity and blow off some of the CO2 atmosphere, it would be worth it. Although I agree it would still be a long term proposal as you wouldn't want to be on the surface for quite a while. Another problem might be the release of other undesirable chemicals, along with H20, especialy sulfur, which venus already has to much off.

Yes -- NO natural impacts of that speed... Stellar masses mergers and black hole accretion events in the middles of the galaxies an the globular clusters - yes, but on the discussed distances , and regarding so shalow gravity wells as the one of our yellow dwarf star - NO... Moving planetoide masses with tens of times bigger than any gravito-dynamically naturally achievable speeds is technologically feasible - the figures come out for known kinds of propulsion... Orion-style, tapping significant amounts of sola energy, UTILIZING the natural enormous stockpile of orbital energy...etc.

I suppose that we don`t need extensive studies of the venusian interior and geology -- only general etimatio of the trapped volatiles content is enough.

The BigSplash will: rotate Venus quicker, will form a moon, will get the atmosphere hotter, wetter and thicker -- but this eases the task - extracting sulfur, CO2, etc... in gaseous form in the atmosphere makes it super-easier to export further - leaving in the final gas/liquid envelope of Venus only the necesarry things...
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Also we shouldn`t underestimate the potential role of the big TNOs as impactor. They are made of water ( even if it occur that vthe venusian interior is geologically devoted of H2O). Their orbital speed is less than 1 km/s. They are numerous.
We could chose TWO kuiperbelt objects of the type of Quawar and Varuna and using produced from their "flesh" termonuclear devices` explosions in Orion-style simply to cansel to zero their orbital motion and to leave thm to fall to the Sun ( we`d need less than 1/10000th of the mass turned in H-bombs). WE must calculate their fall trajectory to intersect with Venusian body, in way so the impactors to hit the planet rom the opposite side, under certain angle, so the orbiot of the planet to be preserved, but the moon-forming, faster axial rotation, etc. to occur. Falling straight down directly from the Kuiper disk, a body should achjieve without aditional boost bigger speed than the comets ( >70 km/s) , with slight Orion-push, the necessary 250-500 km/s for Theia-level event will be achieved.
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The other advantage of the BIgSplash venusian terraforming is that if we use just one impactor the total number of planetary or peri-planetary mass objects of the SolSys doesn`t decreases - with one Vesta or Varuna hitting Venus we receave one new Earth + one new Moon ( quite bigger than the impactor and terraformable on its own -- opposite to the impactors, which are often bad situated and too small for real terraforming...

G.K.

chat · 2005-04-19 04:44:58

karov,

Another option is a kuiper belt object directed at Venus that never quite collides.

A few passes very near Venus will speed up the spin, strip atmosphere from Venus and eventually create the moon as the object looses energy to Venus and is captured in orbit.
No released h20 from the crust this way though, so a full teraform of the remaining venus/moon system will be required.

No long collisional waits for this scenario, but very intense orbital mechanics would be involved.

Austin Stanley,

If the Venus collision was anything like the earth/moon one, i would expect lots of water and lots of iron.
And still many bars of pressure remaining on Venus afterwards.

Rusty oceans resembling earth 4 billion years ago, but with 2x sunlight to deal with and runaway greenhouse problems.

After the few million year wait for it to settle down

karov · 2005-04-19 12:10:06

karov,
Sorry badly typed post on temperature.
600c +- 200c.
600c day side 400c night side.
I agree with your thinking that cooling Venus is not necessarily the best way to teraform Venus.
As you point out we only need to heat Venus another 400 c or so to have co2 escape.
But do we need to heat all of Venus to escape co2?
Or just a small local area of a few km's heated to 1000c-1200c to have the same effect.
Maybe just 10 large focal lenses all pointed at the surface in geo orbit of Venus will do that.
The only power requirements for that is to make the lenses get them to Venus and keep them in geo.
I've always been an advocate of heating Venus to make it more tolerable, or at least make it tolerable for machines on the surface that can survive to continue the teraform.
Collisions with Venus are a great tool for heating Venus, but at a price of recovery time after the collision.
I don't doubt that we could collide anything with Venus, but the recovery wait might be longer than humanity exists.
Small collisions might prove to be a useful tool on Venus, and large ones on solar systems other than ours.

I'm always willing to play, but why is venus such a painful #@$@%@% opponent.

Chat,

1. From where did you get these " 600 c day side 400 c night side" -- the temperature on Venus doesn`t depends on the diurnal cycle, but only to the altitude.
2. Yes, we discussed extensivelly the getting rid of scenarios for venusian atmosphere - particle beams orders of magnitude more intense than the solar wind, x-ray lasers, etc, but I never ment that heating the atmosphere is good way for terraforming. My point is that >90 bars of 500 degrees C of CO2 is not better than say >200 bars of 700 degrees C of water, CO2, sulfur compounds... in both case we must export the escessive material and we could do this via plasmic manipulation and/or orbital rings NO MATTER what the temperature of the gas mixture is -- remember that such methods are proposed to be MINED the SUN and the gas giants first. Boiling the venusian atmosphere to escape velocity is so huge waste of energy AND mainly usefull material, that it shouldn`t be done by any sound civ. The degasated interior of Venus via impact or elseway, indeed ( I`m tired to repeat this time and again) will release enough carbon, oxigen, water, nitrogen to be built THOUSANDS of times the earth`s area in rotating space colonies.

3. The impactor wounded planet - all covered with liquified molten rock, so hot - is net potential of energy for thermodynamical machines to work it -- and is legitimate subject of forced cooling no matter whether the ambient temp. is 400 K or 1000 K. Even hotter is better for the energy extraction work.

karov · 2005-04-19 12:20:22

Chat, see:
--------------------------------------------
Venus Atmosphere

Surface pressure: 92 bars
Surface density: ~65. kg/m3
Scale height: 15.9 km
Total mass of atmosphere: ~4.8 x 1020 kg
Average temperature: 737 K (464 C)
===================================== Chat, note !!!
---------------------------------------------
Diurnal temperature range: ~0
===========================================
Wind speeds: 0.3 to 1.0 m/s (surface)
Mean molecular weight: 43.45 g/mole
Atmospheric composition (near surface, by volume):
Major: 96.5% Carbon Dioxide (CO2), 3.5% Nitrogen (N2)
Minor (ppm): Sulfur Dioxide (SO2) - 150; Argon (Ar) - 70; Water (H2O) - 20;
Carbon Monoxide (CO) - 17; Helium (He) - 12; Neon (Ne) - 7
--------------------------------------------------------
from "Venus Fact Sheet" : http://nssdc.gsfc.nasa.gov/planetary/fa … sfact.html

See: the total mass of the atmosphere is comparable with the mass of the KB or MB impactor body.
BTW, a impactor hitting with 250-1000 km/s actually would penetrate much deep into the planetary solid, passing though the whole air column for much less than a second. Indeed it may occur that the direct influence onto the gas envelope around Venus would be much more insignifficant from the hit itself than intuitively assumed...
---------------------------------------------------
For example with Mars: http://www.universetoday.com/am/publish … ...1842005

See also the Pluto-Haron formation theory.

chat · 2005-04-19 20:04:15

karov,

Not 0c Diurnal temperature range on the surface.

The Pioneer Spacecraft in December 1978 revealed very high winds aloft in its atmosphere, approaching speeds of 200 mph. Along with the thick cloud cover, this could explain why the night side of the planet has temperatures nearly the same as the day side, as strong winds aloft transfer heat around the globe. However it appears that the surface winds are very light.

In short, Venus is by far the hottest planet in our solar system, with a very minimal diurnal temperature spread.

Under the 35km cloud level the temperature does range from day to night.

Quote( I`m tired to repeat this time and again) will release enough carbon, oxigen, water, nitrogen to be built THOUSANDS of times the earth`s area in rotating space colonies)""

What do you propose to do with 85-89 bars co2 and 2 bars nitrogen orbiting Venus?
The energy requirements to do anything with it would have to be staggering.

And don't forget that a 1 bar earthlike Venus will become a runaway greenhouse with 2 x sunlight.
So the remaining bar pressure on a teraformed Venus should be .5 earth or less.
At .5 bar pressure the radiation on the surface of Venus will be 4x that of earth.
Also charged particles will be a big problem on a teraformed Venus.

I've tried to work around this problem and the only solution i could think of was a 4 bar un earthlike Venus.
Or a 1 bar Venus with a permanent orbiting debris ring in geo.

I would also hazard a guess that a strict 92 bar Venus pressure is incorrect.
In the deeper sections probably more like 99 bars.
At the poles also different bar pressures.

My thought on the high speed impactor at Venus is it probably would work to a degree, but a remaining 10 bars co2 is still way to much.
And if the impactor creates a molten Venus for 1,000,000 years is it worth the attempt.

A 1500c Venus from an impactor could easily strip all of the atmosphere of Venus in as little as 100 years.

karov · 2005-04-20 00:28:58

OK. Lets agree on the present surface conditions of Venus that everywhere on it the temperature is > 400 c and the pressure is about 90 bars. With or without impact we have > 10 exp 20 kg of gases in the atmosphere. My point is that to simply blow the atmosphere is pure waste of very usefull materials. I doubt that an impact will disipate significant part of the atmosphere - even warmed to 1500 c, the atmosphere will increae its volume but will cool down to some equilibrium. Even 2000 c would not give us Venus with vacuumed surface in reasonable time. The impact , indeed would get it thicker and hotter, cause massive amount of volatiles will emerge on the surface, when the crust is molten and nothing would capsulate them underneath it. In both cases we should deal with thick and hot or thicker and hotter atmosphere, composed by valuable stuff...
As I undrestand you propose to turn Venus in aka, "chtonic" world, a giant comet, which thick gas envelope to be wethered by intensified solar or other radiation -- the energy requirements from this ARE staggering. The atmosphere if "orbited" will not stay around the planet - it just would partially dissipate, the majority will settle via fall-back...

What I have in mind is the atmosphere of Venus to be "excavated"/ exported off-planet gently, without to be wasted more than the normally technologicaly for the used transport method , amounts.

As we extensivelly discussed we could implement various methods to do this:
1. A system of Orbital rings, provided with shuttle-tanks to suck in portions the atmosphere, begining from the cooler "room temperature" high layers, to put it in tanks in liquid or solid state, and to haul the tanks in cosy orbit around the Sun in order the material to be used in numerous other projects.
2. Plasma - electromagnetically to accelerate particle beams of venusian atmosphere, which to be captured by statites and utilized.

NO x4 times higher insolation with twice rareer atmosphere.

chat · 2005-04-20 05:06:45

karov,

I agree that blasting Venus with huge impactors to eject the atmosphere is a waste of the atmosphere.
Probably not a good idea to just dump 90ish bars of co2 into the inner solar system anyway without some sort of control.

A realistic controlled option of what to do with the atmosphere is a sticking point with Venus.
A chunk of it going to teraform mars would be ideal, but still leave you with maybe 85 bars left.

I have no realistic method to teraform Venus with our current technology.
Lots of ideas on how to go about the teraform but they all break down with the increased sunlight on a teraformed Venus.

Venus is a very bad juggle with bar pressure and boiling water points.
The juggle at any bar pressure is so close to the boiling point of water at the equator that I'm not sure a normal unassisted teraform is possible.
At minimum teraforming Venus might require constant planetary cooling to keep the boiling point down.

As you pointed out even a high speed impactor will settle out with Venus retaining a still pretty thick atmosphere as the equilibrium of the co2 falls below the escape velocity of co2.

If the h20 isn't in the crust as expected a large impactor will just make a much worse Venus.

I'm not sure what would happen to escape velocity co2 at Venus.
I believe once liberated from the atmosphere the majority is dispersed by the solar wind, but a small percent returns to Venus.

I also agree that any teraform attempt at Venus will require staggering amounts of energy.

Thinking about it only causes the occasional headache,
and lots of coffee, no real energy other that boiling the water.

karov · 2005-04-20 07:03:53

Something mind refreshing: The Asteroid Impact Simulator at:
http://www.lpl.arizona.edu/impacteffect … cteffects/

also the linked article - http://www.lpl.arizona.edu/~marcus/effe … ffects.pdf
============================================
Look what is the result from this online impact simulator for 220 km diameter iron impactor hitting Earth ( understand Venus in our case) with 2000 km/s:
----------------------------------------------------
Your Inputs:
Distance from Impact: 20000.00 km = 12420.00 miles
Projectile Diameter: 220000.00 m = 721600.00 ft = 136.62 miles
Projectile Density: 8000 kg/m3
Impact Velocity: 2000.00 km/s = 1242.00 miles/s (Your chosen velocity is higher than the maximum for an object orbiting the sun)
Impact Angle: 30 degrees
Target Density: 1000 kg/m3
Target Type: Ice
Energy:
Energy before atmospheric entry: 8.92 x 1031 Joules = 2.13 x 1016 MegaTons TNT
The average interval between impacts of this size is longer than the Earth's age.
Such impacts could only occur during the accumulation of the Earth, between 4.5 and 4 billion years ago.
Major Global Changes:
The Earth is strongly disturbed by the impact, but loses little mass.
36.09 percent of the Earth is melted
The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.
Crater Dimensions:
Transient Crater Diameter: 9710 km = 6030 miles
Transient Crater Depth: 3430 km = 2130 miles
Final Crater Diameter: 32200 km = 20000 miles
Final Crater Depth: 6.73 km = 4.18 miles
The final crater is replaced by a large, circular melt province.
At this impact velocity ( < 12 km/s), little shock melting of the target occurs.
Melt volume = 3.31 times the crater volume
At this size, the crater forms in its own melt pool.
Thermal Radiation:
Time for maximum radiation: 44.7 seconds after impact
Your position is inside the fireball.
The fireball appears 871 times larger than the sun
Thermal Exposure: 8.72 x 1013 Joules/m2
Duration of Irradiation: 1.16e+06 seconds
Radiant flux (relative to the sun): 75100
Seismic Effects:
The major seismic shaking will arrive at approximately 4000 seconds.
Richter Scale Magnitude: 15.5 (This is greater than any earthquake in recorded history)
Mercalli Scale Intensity at a distance of 20000 km:
The air blast will arrive at approximately 60600 seconds.
Peak Overpressure: 2.76e+08 Pa = 2760 bars = 39200 psi
Max wind velocity: 13400 m/s = 29900 mph
Sound Intensity: 169 dB (Dangerously Loud)
------------------------------------------------------

Interesting but the axial rotation and the orbit doesn`t change much. Possible reason - the impactor simulator is not desidned to deal with such great speeds, second...

Some notes about the relation angular momentum/rotational energy? How actually the impacts under glancing angles change the rotation rate of the target depending on their mass/speed... How much effectivelly the impactor transferes its linear motion kinethic energy in rotation velocity of the target..?

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