Possible to terraform just part of a planet?

Yeah I could see this, and actually I think this is a bit more realistic than most terraforming plans due to the smaller scope, and more predictable means of control.

I would have to go with the idea it is possible. After all, we do something similar here on Earth all the time. Using greenhouses or biospheres to change climate conditions on a localized basis. Same principle I would say.

tehWatcher said:

I would have to go with the idea it is possible. After all, we do something similar here on Earth all the time. Using greenhouses or biospheres to change climate conditions on a localized basis. Same principle I would say.

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Well you can't set up house on most of the earth since it is mostly ocean. You can't grow most plants high in the mountains or in the polar regions or in deserts. So the earth is only partly terraformed...right?

Higgins said:

Well you can't set up house on most of the earth since it is mostly ocean. You can't grow most plants high in the mountains or in the polar regions or in deserts. So the earth is only partly terraformed...right?

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Actually, I was going more abstract. A statement of the underlying concept and not a specific implementation as a means of showing that we have, indeed, managed to terraform on a limited scale here on Earth.

True, one cannot grow a coconut tree at the north pole with natural conditions prevailing, however, one can alter those conditions to allow for that tree to grow in such a location. The method, for the sake of answering the original post, is not relevant. Only that 'habitability' could be, and has been, created and maintained.

tehWatcher said:

Actually, I was going more abstract. A statement of the underlying concept and not a specific implementation as a means of showing that we have, indeed, managed to terraform on a limited scale here on Earth.

True, one cannot grow a coconut tree at the north pole with natural conditions prevailing, however, one can alter those conditions to allow for that tree to grow in such a location. The method, for the sake of answering the original post, is not relevant. Only that 'habitability' could be, and has been, created and maintained.

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As I recall from reading classic sci-fi...there used to be a convention that the "deep valleys" around the "canals" on Mars had a very different "terran-style" climate from the high cold regular parts of Mars.

This wouldn't quite work on earth were for example valleys in the arid SW may have water in the lower areas but they also don't get as much sun and cold air flows down them from higher ground.

Higgins said:

Well you can't set up house on most of the earth since it is mostly ocean. You can't grow most plants high in the mountains or in the polar regions or in deserts. So the earth is only partly terraformed...right?

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Um, this doesn't make sense. All of that, oceans, mountains, deserts, and polar regions are features of planet Earth. Are you saying part of our planet isn't Earthlike?

Hmm.

Higgins said:

As I recall from reading classic sci-fi...there used to be a convention that the "deep valleys" around the "canals" on Mars had a very different "terran-style" climate from the high cold regular parts of Mars.

This wouldn't quite work on earth were for example valleys in the arid SW may have water in the lower areas but they also don't get as much sun and cold air flows down them from higher ground.

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Excellent observation.

In such cases, paraterraforming, as it is called, would most likely be used. A modular approach to terraforming that can be tailored to both population growth and terrain style.

Pthom said:

Um, this doesn't make sense. All of that, oceans, mountains, deserts, and polar regions are features of planet Earth. Are you saying part of our planet isn't Earthlike?

Hmm.

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If the point of terraforming is to make an environment where you can walk out your front door in your pajamas around 10AM and eat some tasty, nutriotious fruit growing naturally right there outside, then most of the earth is not terraformed.

Well we can hope that terraforming allows for some creativity. Imagine being the one responsible for introducing pesky mosquitos to mars for the sake of authenticity.

From Wikipedia: "Terraforming (literally, "Earth-shaping") of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, temperature, surface topography or ecology to be similar to those of Earth to make it habitable by humans."

The livability of our planet depends on those areas where we can't live, or can't live comfortably. Without our vast oceans, arid deserts, polar ice, high mountain ranges, our lovely verdant valleys full of corn and tomatoes wouldn't exist. I really doubt it's possible to just "fix" one section of, say, Valles Marineris, supplying it with atmosphere, fresh water, pastures for goats, and bikini weather, without also fixing the rest of the planet to support such a place.

If you were able to manage such a feat, I believe you'd need such a high amount of energy to support it, as to make it the most expensive real estate in the universe.

Pthom said:

If you were able to manage such a feat, I believe you'd need such a high amount of energy to support it, as to make it the most expensive real estate in the universe.

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I'll second that. In my personal opinion, I would say viable terraforming may come about from nanotechnology. Changing the target planet on the atomic-level instead of with huge machines. The cost of such reshaping would be drastically reduced i'd say if the machines used to terraform the target could be built from the raw material of the planet itself and wouldn't necessarily need to take the form of large planet processors.

Again, though it's my opinion and is not, i'm sure, original.

Addendum:

That's not to say that one may sprinkle nanorobotic "pixie-dust" on a planet and change it, as the mechanics and time-scales involved would not be simple or short. But as a possibility it might just be a useful avenue to explore.

Well, I think you might be able to make a little Martian "garden of Eden" spot using advanced nano-tech, but without the rest of the planet to support it, it would soon fizzle. For an example of something similar, check out the results of last century's "Biosphere" project.

Pthom said:

Well, I think you might be able to make a little Martian "garden of Eden" spot using advanced nano-tech, but without the rest of the planet to support it, it would soon fizzle. For an example of something similar, check out the results of last century's "Biosphere" project.

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Your right. I had strayed from the spirit of the original post and was describing a planet-wide transformation using nanotech. My apologies.

It seems to me that it would have to be in a closed/dome, controlled enviornment. Where else are you going to get an oxegen/nitrogen mix? Also, Mars doesn't have a magnetosphere to ward off deadly radiation. This begs for a controlled enviornment.

Tri

To be fair, the original question didn't specify Mars. I used it only because several of my stories feature Mars as a base for my characters (I don't bother with terraforming--K.S.Robinson did that already, and much better than I might).

But I agree with Tri, in that unless you have gobs of time (centuries), super high tech (nano-machines on steroids), and an unlimited budget, you're kinda stuck with a dome or some other way to contain your environment.

Higgins said:

If the point of terraforming is to make an environment where you can walk out your front door in your pajamas around 10AM and eat some tasty, nutriotious fruit growing naturally right there outside, then most of the earth is not terraformed.

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That is not what terraforming means, and it is impossible to have a planet with the same conditions everywhere. Terraforming comes from terra-earth and means forming a planet into earth-like conditions.

As for the op, you can of course build, what amounts to huge greenhouses on a planet. The problematic thing is the athmosphere, if you're not under some kind of fishbowl you need the whole planet to have an earthlike athmosphere which means you have to terraform pretty much the whole thing.

One possible exception is if you have a planet with vegetation and earthlike atmosphere but incompatible biology. Here it is possible to only terraform a part by sterilizing the area and planting terran vegetation, while the rest of the alien biosphere can still be used fro providing a breathable atmosphere.

Put a city in a large crater on your planet and fill up the crater with oxygen/nitrogen. The planet needs to be big enough to have enough gravity to hold the oxygen in the crater. And the preexisting atmosphere would have to contain nothing heavier than oxygen. Even with not much wind some oxygen would leak out, but if the inhabitants could keep up with oxygen production...
I think it's dangerous and workable.

vr88 said:

I think it's dangerous and workable.

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And a very, very delicate balance. The biggest problem is that we (living things on earth) turn oxygen to CO² when breathing which is unfortunately heavier than oxygen. A crater such as that would lose oxygen at a tremendous rate. Of course, if the whole planet has readily avaiable oxygen reservoirs, maybe an oxide gas as athmosphere or simply normal sand (silicon oxide) it is a simple question of power. A few fusion reactor should provide enough power for electrolysis to have a constant output of oxygen in the crater that keeps the athmosphere breathable. The question is wether that is really preferrable to putting a lid on it. I don't know where i've seen it, but i remember images from a SF movie or something where people created habitats on the moon by simply putting glass roofs over deep canyons. Of course, such habitats would require artificial illumination and'd be built pretty vertical, but using natural cavities would be a lot easier and cheaper than building big domes on flat land. You don't have to make them really airtight, minor losses should be easy to compensate. Though that is still more of a problem on a planet/moon without athmosphere compared to one with an inert athmosphere.
Not to mention that the only planets with no wind at all are ones without an athmosphere. The thermal differences between nightside and dayside as well as a between equatorial and polar region means you always get weather on a planet with an athmosphere.