PDA

View Full Version : Terraforming mars or venus which ones better



VenusROVER
2006-Mar-26, 09:19 PM
I'd say venus lets here you responses

Launch window
2006-Mar-26, 09:32 PM
One theory is that Venus is a crazy planet, right now we might be terraforming our Earth for the worse ( CO2 global warming ) but terraforming a planet is still science fiction. Even if we develop terraforming technology and make the planet less hostile but because we can't find craters on Venus there is the idea that Venus re-surfaces itself once every few hundred million years, thus destroying all your terraforming work. Think of the most hellish re-surfacing on Venus such as Krakatoa or Mt St.Helens times a thousand, anyway as our Sun gets bigger and redder in the next few million years we need to start thinking of building a spacecraft that will have us moving out away from Earth and Venus not inward.

VenusROVER
2006-Mar-26, 09:36 PM
I see

VenusROVER
2006-Mar-26, 09:38 PM
but i asked what would be better venus or mars. To me venus because venus is almost the same size as earth it has a magnetoshpere and a thick carbon dioxide atmosphere. And tell me more about the remodling of venuses surface every couple o million years

Launch window
2006-Mar-26, 09:45 PM
Even though it may be almost impossible to terraform I think Venus is still one of the most important planets to study, in astronomical timeframes our Earth will soon start heating up like Venus. A few hundred million years ago the dinosaurs existed but they are now extinct, our Sun will go Red-Giant in 4500 million years or 4.5 billion but long before that it is suspected by some scientists that in about 700 million years our Sun will just get too hot for life on Earth.

The study of the Venusian surface and atmosphere of the planet Venus is also highly important for exo-planet studies, we are finding hundreds of extra-solar worlds beyond our solar system and many of them lie close to their stars just like Venus and Mercury are close to the Sun, so studies of Venus will help us know more about exo-worlds.

01101001
2006-Mar-26, 09:51 PM
And tell me more about the remodling of venuses surface every couple o million years
I believe the conjecture was resurfacing on the order of several hundred million years.

This was just in the news, from the 2006 Lunar and Planetary Science Conferenc (LPSC).

BBC: Doubt cast on Venus catastrophe (http://news.bbc.co.uk/1/hi/sci/tech/4815230.stm)


Accepted views of how the planet Venus evolved are challenged by new age dates for its surface.

Massive volcanism 500 million years ago was thought to have covered over much of the planet's ancient features.

But work carried out at Imperial College London, UK, suggests a "volcanic catastrophe" is not needed to explain the look of Venus's surface.
Abstract: CATASTROPHE NOT REQUIRED: A NEW STEADY-STATE MODEL OF VENUS (http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1269.pdf) (PDF)

Launch window
2006-Mar-26, 09:53 PM
read this link
http://mac01.eps.pitt.edu/harbbook/c_ix/chapter_9b.htm
It tells you about the Russian and American missions to Venus

There is a new mission on its way to the planet
Venus Express (http://www.bautforum.com/showthread.php?t=39158)
http://www.bautforum.com/showthread.php?p=445445#post445445
it arrives in about 2 weeks time

Launch window
2006-Mar-26, 09:59 PM
I believe the conjecture was resurfacing on the order of several hundred million years.

This was just in the news, from the 2006 Lunar and Planetary Science Conferenc (LPSC).

BBC: Doubt cast on Venus catastrophe (http://news.bbc.co.uk/1/hi/sci/tech/4815230.stm)


Abstract: CATASTROPHE NOT REQUIRED: A NEW STEADY-STATE MODEL OF VENUS (http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1269.pdf) (PDF)

thanks for that ! its amazing that we know so little about this planet, I'll try and find out more about this steady-state model for Venus

aurora
2006-Mar-26, 10:36 PM
I'd say venus lets here you responses

Venus has some real problems for anyone trying to venture to the surface.

One is how to get rid of most of the atmosphere to allow for cooling, and another is how to get water since there is none on the planet.

antoniseb
2006-Mar-26, 11:21 PM
Venus has some poisonous isotope ratios that would be hard to overcome, but if money and effort were no object it would probably be a better option, given the extra surface area.

ryanmercer
2006-Mar-27, 01:24 PM
Venus in my opinion. It is similiar in size to earth, it is fairly smooth... the only issues you have are, well coming up with terraforming technology that could do it's job in a few hundred years, find some way to get all of the c02 out of the atmosphere and fast (so you could even start terraforming) and have a reason to even bother that would make it cost-effective.

GOURDHEAD
2006-Mar-27, 02:52 PM
I recommend "simultaneous" terraforming of Mars Venus and the moon. The first step will be to design and develop a space transportation system with sufficient robustness equal to or better than http://home.comcast.net/~mbmcneill7/ . True, Venus will get scorched before the Earth and Mars when the sun expands, but consensus has this happening a few billion years hence which makes it worth the effort.

Both the moon and Mars could benefit from 5 bars (an arbitrary guess) of the Venusian atmosphere which we have to reduce/transform in order to cool Venus sufficiently. Venus has about three bars of nitrogen of which the moon and Mars could use one each as an oxygen buffer after suitably modified microbes have modified their atmospheres to contain 23% or so free oxygen (like back home). With 5 bars of atmosphere the surface temperature of Mars can be maintained at a comfortable level for humans and such agriculture as we wish to practice and liquid water will become available from the currently existing ice which can be supplemented with material from the icy smaller moons of the gas giants and Kuiper belt objects. Similar modifications will make the moon a more comfortable place for humans to inhabit. These atmospheres won't permanently remain on either the moon or Mars, but they will likely last for several hundred million years during which time we will get smarter and better equipped to maintain them in place. If needed, magnetic fields can be provided using a network of carbon nanotube conductors (another use for all that atmospheric carbon at Venus) in orbit about each object (the design of these is left as an exercise for the reader).

Venus will get a lot of water from the breakdown of the sulfuric acid clouds, and if more is needed, we can get it from the sources mentioned above.

If we are to become the self-appointed custodians of the MW, and then the universe, we need to get started. I'll be the idea person, you can do the hard work, provide the financing, and take the risks--after all there are a lot of you out there.

Nicolas
2006-Mar-27, 05:11 PM
Is there any advantage in terraforming Venus to save us from an expanding sun versus reforming our own Earth?*

To me, it seems we need to come from less far if we'd alter earth instead of Venus or Mars.

All are science fiction though.


*if we "just" want another planet to live on next to earth, this doesn't count of course.

Terra Nova
2006-Mar-28, 01:10 AM
We would probably faster find another Earth type planet in other star systems to colonize before any kind of terraforming of Mars and Venus takes place.

Ilya
2006-Mar-28, 01:48 AM
One is how to get rid of most of the atmosphere to allow for cooling, and another is how to get water since there is none on the planet.
Getting water to Venus is "relatively easy" -- diver a large comet to hit it. Getting rid of all the CO2 is harder. Breaking it down with algae won't cut it -- if you separate 90 atm of CO2, you will get a layer of carbon almost 100 meters thick and 60 atmospheres of pure oxygen. They won't stay separated for long! :)

The closest I saw to a doable way to do this is to drop on Venus enough metallic calcium or magnesium to react with all carbon dioxide:

3Ca + 2CO2 => Ca(CO)2 + 2CaO

Both reaction products are solid precipitates.

As to where to get that much alkaline metal... Got a 100 km calcium-magnesium asteroid handy?

lord bytor
2006-Mar-28, 03:18 AM
Venus is tempting because of it's similar size and with its placement in the solar system you would think you could have a nice warm climate over the entire planet but you got a few really big problems. Venus has alot of carbon dioxide... a whole lot of carbon dioxide, I've seen estimates that if you were to precipitate
the carbon dioxide out in the form of carbonates it would be a close to a mile thick on the surface. Someone already mentioned the lack of water on Venus but it's atmosphere is also deficient in nitrogen which you would really need to make an earth-like planet, you could perhaps start importing it from other parts of the solar system, like Titan but that's quite an endevour to ship that much nitrogen.

However the real show-stopper is the Venusian day. With a rotation of 243 days there is no way you could ever have anything like an earth like climate.

Jens
2006-Mar-28, 03:32 AM
I say we'd better start thinking seriously about terraforming the earth before we think about Mars (and I think Venus is unreasonable).

Van Rijn
2006-Mar-28, 04:16 AM
I'd say Mars with no hesitation. We're on the edge of the technology required to give Mars a much more useful environment. Venus is insanely more difficult. You would need to cool the planet down for centuries using a giant sun shield, do something with all the excess CO2, add lots of water, provide a permanent sun shield to reduce the sunlight level, either increase rotation (somehow) or artificially provide a reasonable day/night cycle - again with very large (thousands of KM/miles in diameter) reflectors above Venus.

I would expect to be building O'Neill habitats or even more advanced habitats long before we would try to "terraform" Venus.

With Mars, on the other hand, you can meet it halfway. Simply increasing the atmospheric pressure makes it much easier to build habitats there. That's something you can build on - do other things to improve the Martian environment over time.

Nicolas
2006-Mar-28, 07:00 AM
I'd say we're only on the edge of that technology if you take a very thick edge and place us on the extreme left of it :).

What would be really nice is to get rid of a tiny bit (terraform wise) of excess CO² and the like on earth first.

Van Rijn
2006-Mar-28, 07:31 AM
I'd say we're only on the edge of that technology if you take a very thick edge and place us on the extreme left of it :).


I disagree. I'm talking about halocarbon greenhouse enhancement and moderately sized orbital reflectors to warm the poles, made of very thin material. Yes, we would need a very good reason to go there and do it, but the technology isn't very far fetched. And I'm not suggesting you'd get instant earth - but you could raise the atmosphere pressure significantly in a century or so.

Venus would require a sunshade roughly the diameter of the planet to cool it off. And that's just to start. Importing water, the permanent shading and so on require some truly impressive improvements in technology.

Now, there may be some changes during this century. I strongly suspect we will develop self replicating machinery (macroscopic at first) within the century and that would give you a way to quickly multiply your effort. But we certainly don't have that technology yet.



What would be really nice is to get rid of a tiny bit (terraform wise) of excess COČ and the like on earth first.

Of course, we already know of ways to do that. But that's a different subject.

Nicolas
2006-Mar-28, 08:18 AM
The pole warming technology isn't really very far fetched, but still extremely difficult for us to do. We fail to deploy a moderately sized reflector as a test (but I'm sure we could do that with some practice, it ain't that extremely hard) and fail to produce any selfdeployable lightweight sail larger than 100m in diameter at the moment (that's a bigger problem). We'd need a lot larger reflector to warm the martian poles.

What do you mean with halocarbon greenhouse enhancement?

agingjb
2006-Mar-28, 09:29 AM
Full scale terraforming of anywhere is a very long way off, even Mars. Substantial and sustainable habitats off-Earth are slightly more plausible within the century - the Moon, Mars, in space, and within NEOs. I'd guess that NEOs would give the best return in office space.

Van Rijn
2006-Mar-28, 09:43 AM
The pole warming technology isn't really very far fetched, but still extremely difficult for us to do.


Agreed. It is the sort of thing we could do if there was a really important reason to do it, but it would be very hard and very expensive.



What do you mean with halocarbon greenhouse enhancement?

Halocarbons are extremely efficient greenhouse gases - many thousands of times more efficient than CO2. It would take a relatively small amount (though still a lot) to increase the temperature of Mars substantially. It is thought there would be a point where there would be an increase in air pressure due to C02 regolith release and CO2 staying unfrozen that would further increase the temperature.

Of course, "relatively small" is still a very great deal for a civilization that has never put a person on Mars. And we really need to know more about the details of the Martian CO2 inventory before we can accurately determine the requirements.

Here is one short article that mentions this subject and others - but I think it is a bit too optimistic given current information:

http://www.users.globalnet.co.uk/~mfogg/zubrin.htm