[sundog]

If we had the technology, would Mars really be a suitable
candidate for terraforming?

Correct me if I'm wrong, but as I remember it, Mars has only
about 1/3 the gravity of Earth and because of this, it lost
most of its atmosphere to solar winds. So even if we had the
ability to create a breathable atmosphere on Mars, wouldn't
it just blow away again?

We have ideas about warming Mars, would Venus be an option
if we could cool it? Or is it just too close to the Sun?



sundog

[BlameTheEx]

sundog

Define the technology. With sufficient technology we can do anything we please.

Yes, Mars will loose any atmosphere we were to give it, but it would take millions of years for the loss to become significant. If we had the power to give mars an atmosphere then presumably we would have the power to maintain it.

Earth is habitable, but it won't remain that way for a population of our current size for millions of years without an even greater level of active maintenance. At least it won't with us chopping down forests and burning fossil fuel at current rates.

Venus is generally considered far harder to teraform than Mars. Cooling might be possible. A shield between it and the Sun might do the trick.

The surface temperature of Venus is much higher than would be expected from it's distance to the Sun. The cause is an atmosphere 90 X that of Earth, and principally carbon dioxide. One hell of a greenhouse effect. That is a lot of atmosphere to alter.

Even if the temperature and atmosphere could be sorted there is one last problem - One Venus day = 243 earth days. That is bound to lead to rather unsettled weather.

[Tormod]

Yes, with Venus the length of the day is probably a larger problem than the carbon dioxide.

Blame - are you sure that Mars can hold any atmospheric pressure at all? I don't see how we could maintain an atmosphere there. At least (like sundog mentions) the solar wind just blows everything away. How would we go about that? Do you know about any relevant sites for more info about this?

[sundog]

Originally posted by: BlameTheEx
With sufficient technology we can do anything we please.
...
If we had the power to give mars an atmosphere then presumably we would have the power to maintain it.

Hi BlameTheEx,

I Agree, by the time we actually start terraforming we may indeed have
the technology to maintain the atmosphere. Heck, we may even have
interstellar travel by then and find a more suitable planet.

The web sites I have been reading mention a few ways of warming Mars.
Some of these processes seems awfully slow, that's what made me wonder
about the solar wind.

One radical idea is to impact Mars with large icy asteroids containing
ammonia. The impact would warm the planet by a few degrees and also
add tons of greenhouse gas and water. Although this may be a faster
method, human settlement would be delayed for centuries.

Originally posted by: BlameTheEx
One Venus day = 243 earth days.

Yes, I can see how that would be a problem. I didn't consider the day
length, Venus was more of an after thought.


Well, I guess realization of terraforming is so far in the future that we
can't know what technology we may develop by then. Ultimately, our
distant descendants will be the ones to take up this task. I guess all we
can do right now is learn what we can about the planets and how they
evolve.



sundog

[paultrr]

Its been speculated before by people at NASA. Yes, add in the proper greenhouse gasses, something we seem damn good at making, and Mar's atmospheric pressure can be raised. It will leak off, so does our atmosphere for that matter leak into space. The worst problem Mars has is the lack of a strong magnetic field. You simply do not have the radiation shielding we have on earth. What's needed besides raising the atmospheric pressure, and oxygen, is life which tends to recycle things here on earth. Green Plant life and water are amongst several things Mars would need to be properly terraformed. Mars has water from what we can tell now. The simplest way to live on Mars is in pressure domes at the present. I suspect the soil there given an atmosphere and liquid water can sustain plants. So raising crops to feed people under domes is possible. One thing nice on the power generation issue is water can be broken down into oxygen and hydrogen. Hydrogen fuel while explosive is also very clean to burn for powering generators, power cells, etc.

[paultrr]

Venus had water in its past from what we can tell. That water is now very much boiled away. The carbon dioxide would have to be lowered as well as the overall temperature. Venus is far worse a choice to terraform at the present than Mars. There is also a reason not to go inward for other worlds to live on. As our Sun ages it gets hotter. Eventually even the earth will not be the place to live. If we want to find long term worlds to live on we need to go outward, perhapos even one day to other systems.

[BlameTheEx]

Tormod

Originally Posted by Tormod

Blame - are you sure that Mars can hold any atmospheric pressure at all? I don't see how we could maintain an atmosphere there. At least (like sundog mentions) the solar wind just blows everything away. How would we go about that? Do you know about any relevant sites for more info about this?

I am indeed. Mars still has some atmosphere left after billions of years. Loss must be slow.

Of course the question arises as to where we would find an atmosphere for Mars.

If it was extracted from the soil, It would be the equivalent of extracting ALL the oxygen from the soil for the whole surface for some meters of depth. I dare say you would need the hydrogen and nitrogen too. That to me rules out any sort of biological process within any reasonable time scale. Nothing more complex than bacteria or lichen is plausible, and you would need very long roots to dig that far.

I would root for brute force rather than biology. Nuclear power to bake the atmosphere out of the rocks, or crash asteroids. Perhaps volcanoes can be reawakened? All a bit drastic.

But for more well thought out opinions than mine, I think you will find just about everything here:

http://www.redcolony.com/artindex.php?type=Terraforming

[Stargazer]

We could terraform Mars, the questions are how long can we accept it to take, how close to an Earth like environment do we want it to be, and how much are we ready to spend... To alter the atmosphere and climate could be done in a number of ways. The most efficient way would probably be to spread genetically engineered plants and microorganisms on the surface, that could spread out by itself and change the atmosphere. The water could be melted perhaps by using giant mirrors to focus the sunlight on the polar ice caps, though I guess it's easier to cover it with black dust of some sort or another.

Venus is difficult for many reasons, mainly I guess because of the long days, as already been mentioned, but also because there's plenty of atmosphere that has to be done away with and the rest mnust be changed.

The moon could be a candidate, but only in the form of an oasis or several, under transparanet domes for example. Or perhaps why not build a worldhouse ? :)

Then we have Ganymede and Callisto, could something be done about those too?

[Stargazer]

Originally Posted by sundog

Well, I guess realization of terraforming is so far in the future that we
can't know what technology we may develop by then. Ultimately, our
distant descendants will be the ones to take up this task. I guess all we
can do right now is learn what we can about the planets and how they
evolve.

Maybe it's so that when we can properly and fairly quickly terraform a planet, we may no longer need to do it? Maybe we could adapt us to harsher environments with genetic engineering. But then I suppose it's pretty difficult to make it possible for us to survive in the Martian environment as well as the Earth environment.

[BlameTheEx]

Stargazer

Travel between the planets will never be cheap. That is via development of current technology. A scientific breakthrough is always possible. Something like antigravity would do. Still, I don't expect it.

Anybody born on mars is probably going to stay put. If genetic engineering makes him/her unfit for earth it will be of little importance. Besides, it would be only one of many problems. Lack of immunity to earth diseases and the risk of bringing them back, Cultural differences, Gravity, Politics.

Frankly, I agree with you. People are likely to adapt to mars as it is, whether through genetic engineering, careful selection of candidates, technology, cultural adaptation, or most probably all of the above.

Martian colonists will be very high-tech. Of necessity most will be city people. A complex industrial society with a small population. They will be a control fanatics used to planning for every necessity. Few will ever spend much time outside their controlled environment domes.

Could such people want to compete with an ecology? Animals with their diseases, Tree roots undermining buildings. Your colonists will want to know how to filter out the bacteria from an atmosphere, how to sterilise the groundwater, lakes and rivers.