Terraforming question; icy moons and planets

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NoXion
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Terraforming question; icy moons and planets

Post #1by NoXion » 10.04.2011, 17:02

My query is this; given that the moons of the outer planets (eg. Callisto, Mimas, Titan and Triton) as well as objects like Pluto, Sedna, Quaoar etc are composed of significant amounts of ice, wouldn't terraformation of these bodies result in worlds completely covered in oceans? Or would the addition of a soil layer be sufficient to protect the rest of the object's volume from the presumably now-much-warmer atmosphere/surface?

I ask this because when I see images of such bodies having been terraformed, they typically have large continents - some pay attention to detail and even base the distributions of landmasses on available height data. But how would that happen if the ice content of a body was anything other than a thin surface layer?
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Re: Terraforming question; icy moons and planets

Post #2by ThinkerX » 10.04.2011, 23:17

1) The objects you describe tend to be too distant from the sun for water to remain in an unfrozen condition - at best you'd end up with a world in a sort of permanent ice age; and

2) they also tend to be too small (have too little mass) to hold a significant oxygen/nitrogen atmosphere - pound for pound and ton for ton, their crust is vastly lighter than the likes of a 'rocky planet'.

Now if such a world were large enough and close enough - say about the same distance out as Mars (and probably *at least* as large as the earth or larger) - and it were terraformed...hmmm...you'd probably end up with a world covered by a very large very cold ocean with extensive ice caps, but without dry land.

That said, one of the recently deemed feasible types of extra-solar planets are pure 'water worlds', worlds that are effectively composed of various types of water all the way through.

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Re: Terraforming question; icy moons and planets

Post #3by NoXion » 11.04.2011, 01:06

ThinkerX wrote:1) The objects you describe tend to be too distant from the sun for water to remain in an unfrozen condition - at best you'd end up with a world in a sort of permanent ice age; and

Perhaps I forgot to mention that in the examples I've seen, they've had a clearly Earthlike surface (complete with atmosphere) that's presumably being kept warm by some non-obvious means. One example being the terraformed Pluto add-on available at the Motherlode. A more comprehensive example is this image of various terraformed Solar System bodies, although the artist of that image did say that he "pretended they had the proper gravity and sunlight, and were made of rocks instead of just ices", which makes me think that when played straight this trope is based on simple ignorance or whimsy.

2) they also tend to be too small (have too little mass) to hold a significant oxygen/nitrogen atmosphere - pound for pound and ton for ton, their crust is vastly lighter than the likes of a 'rocky planet'.

That's another issue, but my understanding was that for a sufficiently massive body (for example, something around the mass of the Moon), atmospheric losses would only be significant on the order of centuries or longer - plenty of time to replenish the atmosphere, a trivial exercise for a civilisation capable of terraforming. But even then, one can sidestep the issue by building a roof to prevent atmospheric losses. But that would still leave the issue of what would happen to a world thus terraformed which has significant amounts of ice in its volume.
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Re: Terraforming question; icy moons and planets

Post #4by Fenerit » 11.04.2011, 01:44

I wonder how the "terraformists" deal with tectonics and the magnetic field in such issues, since their purposes are that of modifying a dead planet to sustain the whole life thereof, and not to make just an "habitative place", thing that a planetary base (buildings) can do best and without too much resources. On geologic scale, the simple atmosphere warming isn't enough. Just a thought.
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Re: Terraforming question; icy moons and planets

Post #5by NoXion » 11.04.2011, 02:15

Fenerit wrote:I wonder how the "terraformists" deal with tectonics and the magnetic field in such issues, since their purposes are that of modifying a dead planet to sustain the whole life thereof, and not to make just an "habitative place", thing that a planetary base (buildings) can do best and without too much resources. On geologic scale, the simple atmosphere warming isn't enough. Just a thought.

I don't think plate tectonics are all that relevant to terraformation. Why should they be?

Also I think magnetic fields are overrated. Even in their absence, a breathable atmosphere would provide more than enough shielding from cosmic radiation.
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Re: Terraforming question; icy moons and planets

Post #6by ThinkerX » 11.04.2011, 03:48

'science thrown out the window' about sums that up.

As far as terraforming other bodies in the real solar system, the best option, far and away, would be Mars.

Kim Stanely Robinson in his 'Mars' trilogy (fiction, with a lot of science thrown in) took the most readable comprehensive stab at this...but even in his somewhat optimistic, an intensive everything goes just right scenario/program, it still took a good couple hundred years of intense effort to provide (the lower regions) of Mars with a breathable atmosphere. Three or four hundred years - again, assuming a steady, major effort - is more realistic.

The only other serious option for terraforming in the solar system would be Venus; problem is it orbits inside the suns 'habitable zone' (where water remains liquid).

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Re: Terraforming question; icy moons and planets

Post #7by NoXion » 11.04.2011, 05:22

ThinkerX wrote:'science thrown out the window' about sums that up.

As far as terraforming other bodies in the real solar system, the best option, far and away, would be Mars.

Kim Stanely Robinson in his 'Mars' trilogy (fiction, with a lot of science thrown in) took the most readable comprehensive stab at this...but even in his somewhat optimistic, an intensive everything goes just right scenario/program, it still took a good couple hundred years of intense effort to provide (the lower regions) of Mars with a breathable atmosphere. Three or four hundred years - again, assuming a steady, major effort - is more realistic.

That depends on your definition of "realistic". To illustrate, there is a huge difference between "doesn't break any known laws of physics" and "is achieveable in the foreseeable future". I haven't read the Mars trilogy, but I would assume that it leans towards the latter. Ultra-hard science fiction would likely not have terraforming at all, in my estimation.

The only other serious option for terraforming in the solar system would be Venus; problem is it orbits inside the suns 'habitable zone' (where water remains liquid).

Actually, I always understood that Venus was just inside the "habitable zone", and that the main difficulties in terraforming it are reckoned to be its slow rotation (longer than its year!) and the substantial atmosphere which would be a pain in the fundament to get rid of.
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Re: Terraforming question; icy moons and planets

Post #8by ThinkerX » 11.04.2011, 06:01

That depends on your definition of "realistic". To illustrate, there is a huge difference between "doesn't break any known laws of physics" and "is achieveable in the foreseeable future". I haven't read the Mars trilogy, but I would assume that it leans towards the latter. Ultra-hard science fiction would likely not have terraforming at all, in my estimation.

A fair enough point, though I'd also have to point out that using 'gravity generators' of some sort and some unknown means of substantially raising the temperatures of say...the Jovian moons or other icy bodies either breaks the known laws of physics or gets close enough to it to where it doesn't matter.

And as to the 'Mars' trilogy, yes it very much leans towards what "is achieveable in the foreseeable future". Enough so to the point where if some future world government decided to terraform Mars, it is probably pretty similiar, at least in outline, to how they'd go about it. But it would also be a long term project (maybe they'd sell it as a 'jobs for life' thing, as a project like this would employ millions).

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Re: Terraforming question; icy moons and planets

Post #9by NoXion » 11.04.2011, 07:25

ThinkerX wrote:A fair enough point, though I'd also have to point out that using 'gravity generators' of some sort and some unknown means of substantially raising the temperatures of say...the Jovian moons or other icy bodies either breaks the known laws of physics or gets close enough to it to where it doesn't matter.

There's no need for gravity generators if you can maintain an atmosphere through replenishment of losses, and the issue of heat can be fixed with foil mirrors and/or fresnel lenses. It might sound grossly wasteful, but consider the trivial uses we now put what used to be considered precious commodities to, like aluminium.

Although I think in such cases paraterraforming would be the better option, at least at first.

And as to the 'Mars' trilogy, yes it very much leans towards what "is achieveable in the foreseeable future". Enough so to the point where if some future world government decided to terraform Mars, it is probably pretty similiar, at least in outline, to how they'd go about it. But it would also be a long term project (maybe they'd sell it as a 'jobs for life' thing, as a project like this would employ millions).

A world government... based on Earth? Wouldn't the (human) Martians actually living there want a say in the matter? ;)
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Re: Terraforming question; icy moons and planets

Post #10by Fenerit » 11.04.2011, 13:16

For what is worth, for an introduction about how the magnetic field prevent the atmosphere loss: http://en.wikipedia.org/wiki/Atmospheric_escape. Instead, for the importance of tectonics and in particular the rock cycle for the water and the carbon cycle: http://www.morning-earth.org/graphic-e/biosphere/Bios-Pr-ROCKCYCLE.html. Of course, I've said, these issues are importants on long scale and for an inclusive concept of "terraforming", that be not like a planetary "outpost".
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Re: Terraforming question; icy moons and planets

Post #11by ThinkerX » 12.04.2011, 00:11

A world government... based on Earth? Wouldn't the (human) Martians actually living there want a say in the matter?

This is actually one of the main plot drivers in the 'Mars' series. Apart from that, considering it would take a good couple centuries minimum before you could breathe the air and avoid hypothermia while doing so, who would actually want to live on the planet while the terraforming is in progress? Especially since much of that terraforming would be extremely dangerous to those on the ground (like dropping water ice asteriods miles across onto the surface).


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