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Forum » SpaceEngine » Science and Astronomy Discussions » Terraforming (Discussion of terraforming in general)
Terraforming
midtskogenDate: Wednesday, 13.03.2013, 20:35 | Message # 31
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The best possible term would be "skeptic" I think. It covers how the person thinks and assesses claims without reference to a profession.

A: We don't have to transport 200.000 tonnes of aluminium from Earth because we can produce it on the Martian moons.
B: You can't assume that there is sufficient extractable bauxite.
A: That's an interesting hypothesis. Prove it!

If B is a scientist, I think a perfectly fine answer would be that he can't because we simply do not have sufficient data. I wouldn't even call that position particularly sceptical. Just a pretty accurate description of facts.





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HarbingerDawnDate: Wednesday, 13.03.2013, 23:18 | Message # 32
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Quote (midtskogen)
I wouldn't even call that position particularly sceptical.

A skeptic is someone who does not accept claims that are not supported by evidence. It is the correct term. Also, person B did not present a hypothesis, so person A is clearly an idiot.





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WatsisnameDate: Thursday, 14.03.2013, 00:09 | Message # 33
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You can't assume that there is sufficient extractable bauxite.


This isn't an assumption. There is aluminum present both in the Martian moons (they are essentially captured C-type asteroids), main belt asteroids, and the Martian surface as well. Techniques for extracting this aluminum are also beyond the scope of the paper -- he only mentions the energy required. Discussions of in situ mining/processing of material from other objects in the solar system may be found elsewhere.







Edited by Watsisname - Thursday, 14.03.2013, 00:10
 
midtskogenDate: Thursday, 14.03.2013, 08:33 | Message # 34
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This isn't an assumption. There is aluminum present both in the Martian moons (they are essentially captured C-type asteroids), main belt asteroids, and the Martian surface as well.

You need more than presence. I think it's a safe assumption that all big, rocky bodies of the solar system have a fair mix of metals, the question is if there's a million tonnes of extractable bauxite (or whatever that is required to produce 200.000 tonnes of aluminium). It doesn't help much if the aluminium is thinly spread through the moons. There are several million tonnes of gold in the world's ocean, but there's no method of extracting it that is anywhere near worthwhile.

What evidence do you have for the quantity and concentration at the surfaces?





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WatsisnameDate: Thursday, 14.03.2013, 11:57 | Message # 35
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In carbonaceous asteroids aluminum composes on the order of a few percent by mass. It is not concentrated in easy to mine veins, but rather in Calcium-Aluminum Inclusions (CAI's), which are fairly uniformly distributed throughout. It would require processing a lot of material to get the required amount. It would not be easy. Same for extraction from the Martian surface. As I said quite explicitly in my last post, details for extracting and processing it are beyond the scope of the paper. This paper only mentions the energy required, which is quite satisfactory for its purposes.

Quote

What evidence do you have for the quantity and concentration at the surfaces?


Hmm. No. I don't think this request for evidence deserves my entertaining. It's not very relevant to my interests or that of the paper. And you are the one who is skeptical/interested in the subject. Do your own research. The internet is right at your fingertips. I'll give you some hints though, depending on which surfaces you are referring to:

If you mean asteroids / the Martian moons, then the surface composition is essentially meaningless here, as per what I have said in my first paragraph. Knowledge of bulk composition comes from the study of meteorites.

In the case of the Martian surface, you may look up the results from analyses of surface chemistry/petrology/mineralogy, etc, from our rovers and orbiting satellites. Here's a good hint: The action of surface water often lead to the deposition of aluminum-rich clays. MRO has released some pretty spectacular images from its spectrometer.

If you find an interesting paper which seems like it will give meaningful answers for you, but is not free to view, give me the link and I'll look at it.





 
midtskogenDate: Thursday, 14.03.2013, 12:11 | Message # 36
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If you find an interesting paper which seems like it will give meaningful answers for you, but is not free to view, give me the link and I'll look at it.

Here might be one: http://www.sciencedirect.com/science/article/pii/0016703764900912

So, if typical chondrites have a little over 1% aluminium, it seems that one would have to find an asteroid (or if we're very lucky a Martian moon) that is quite different. On Earth aluminium is extracted from bauxite which has 20% or more aluminium content, as far as I've understood.

Isn't it a bit convenient of the terraforming paper to define the most challenging parts as outside its scope?





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Edited by midtskogen - Thursday, 14.03.2013, 12:13
 
WatsisnameDate: Thursday, 14.03.2013, 12:42 | Message # 37
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(Sort of answering your post backwards here). tongue

Not really, because it is laying out the foundational work. It is showing that given the ability to gather the required resources and work with them, then these results may follow. It does not know or care about how extraterrestrial mining methods will evolve.

Quote
So, if typical chrondrites have a little over 1% aluminium, it seems that one would have to find an asteroid (or if we're very lucky a Martian moon) that is quite different. On Earth aluminium is extracted from bauxite which has 20% or more aluminium content, as far as I've understood.


All that means is that Earth is blessed with aluminum-bearing clays/ores that are richer than asteroids. That means we'd have to process more asteroid material for the same amount of aluminum. It may also mean differences in processing technique. edit: (Obviously; it's different material in a different environment).

Quote
Here might be one:

Okay, cool, it's only 7 pages. Not bad. It basically deals with a few unusual results from measurements of Aluminum concentration in various Chondritic meteorites (some measured anomalously high, others measured zero!). It was generally believed that measurements below 0.5%, or above 2.5% were erroneous, and this paper investigates these data and find that they are indeed erroneous. What caused the erroneous results? Technical stuff, basically revolving around how difficult it is to get accurate measurements of Al2O3.

From their results section, they find the variation in aluminum content within any one meteorite is on the order of +/- 10 percent, and this is even with very small sample sizes of tens of milligrams. They studied ten separate meteorite falls, often with multiple fragments from each fall. They find the aluminum concentration for all the chondrites lie between 1.14 and 1.55 percent, with a mean of 1.33.

Sounds like a pretty robust confirmation of what I have described. smile







Edited by Watsisname - Thursday, 14.03.2013, 12:46
 
HarbingerDawnDate: Thursday, 14.03.2013, 13:27 | Message # 38
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Isn't it a bit convenient of the terraforming paper to define the most challenging parts as outside its scope?

No, because the paper deals with the what and the possible how, not the specific how. And as we've already established, determining how we might mine and process asteroids or planets decades from now is a bit silly, as we have no way to know what technologies and practices will be in use then.





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midtskogenDate: Thursday, 14.03.2013, 13:47 | Message # 39
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Okay, cool, it's only 7 pages.

And they demand $40 if you don't have a subscription or something? This practise should have died when internet took off 20 years ago...

Quote (Watsisname)
They find the aluminum concentration for all the chondrites lie between 1.14 and 1.55 percent, with a mean of 1.33.

Thanks. It's slightly surprising given that the content in Earth's crust is 8.3% (according to Wikipedia). Looks like some process has sorted and half processed the aluminium for us pretty well. Don't expect a rush of prospectors if you tell them that you know a place with 1.5% aluminium content and it's only 50 million km away... smile So we either need a brand new aluminium processing method cheaper than the transport alternative or find an asteroid with an exceptionally high content of aluminium. We don't even know whether either exists at all, which is my point. Ten meteorites may be a small sample, but it doesn't really add much hope of finding shiny aluminium asteroids out there.

To crush 20 million tonnes of asteroid material and process it to extract 200.000 tonnes of aluminium - I don't know. He could just as well have suggested establishing a wormhole from Earth to Mars orbit and said that the construction of such a wormhole apparatus is outside the scope of his paper. Sounds like the space elevator is more realistic than mining.





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HarbingerDawnDate: Thursday, 14.03.2013, 14:27 | Message # 40
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He could just as well have suggested establishing a wormhole from Earth to Mars orbit and said that the construction of such a wormhole apparatus is outside the scope of his paper.

No. We know that processing the aluminum or other materials is possible from experience in mining and processing terrestrial resources, as well as ISRU research, though it would require a large industrial effort. Wormholes, on the other hand, have never been demonstrated at all, and remain hypothetical only. So there is a huge difference.

Quote (midtskogen)
Sounds like the space elevator is more realistic than mining.

Mining would be required regardless, it's just a question of where the mining is taking place. We won't know what the most practical path is until we get to the point where we are ready to being planning the actual terraforming project. Currently we're just studying the idea. Establishing a specific plan of action and beginning to carry it out is something that will not happen for decades, if ever...



This might be a good point to shift gears in this conversation - at least for now - and talk about the ethics of terraforming rather than the methods. Is it right to completely change a planet at all? What if it has life? Should we be allowed to destroy features on another world so that we can better utilize it for our own benefit? etc.

Ethical dilemmas, the oft ignored dark side of terraforming... so let's discuss them!





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WatsisnameDate: Thursday, 14.03.2013, 14:28 | Message # 41
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Quote (midtskogen)
And they demand $40 if you don't have a subscription or something?


I agree, that's pretty ridiculous. wacko

It's interesting that the Earth's crustal composition averages that much higher. I'm not sure if that's a consequence of differentiation, or chemical reactions (probably with water/oxygen). Would be interesting to know. I've often wondered what process causes elements like gold and platinum to exist as they do on the surface/crust, rather than all having sunk to the Earth's core. Must be something regarding thermal activity and water, but I sure don't know the details.

Finding an asteroid with high aluminum abundance (like, greater than 10%) doesn't sound likely at all given the data, but an important consideration here is location. If the asteroid is very close to where we would be applying those materials, then it's not unreasonable to expect that it would be more cost effective to go that route than to ship material between planets. Especially if it's a lot of material that is required.

Your last paragraph strikes me as a brief outburst of silliness. Comparing the challenges of mining with the challenges of wormhole construction is silly. I would not even agree that space elevators are more realistic than mining, but maybe that's just me.

Quote (HarbingerDawn)

This might be a good point to shift gears in this conversation - at least for now - and talk about the ethics of terraforming rather than the methods.


I really like this idea. smile Kim Robinson's Red Mars trilogy has a lot of fun with this subject.







Edited by Watsisname - Thursday, 14.03.2013, 14:39
 
HarbingerDawnDate: Thursday, 14.03.2013, 15:05 | Message # 42
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Kim Robinson's Red Mars trilogy has a lot of fun with this subject.

Indeed, a great read for anyone interested in a hard (fictional) look at interplanetary colonization and terraforming from a very human perspective. Though it did have some extremely dull parts, especially in the first and third books (the latter of which I never finished).

I'm hoping that other people have opinions and thoughts on this topic, as I myself and too conflicted on most of the ethical questions of terraforming to even present an opinion, but I will say that I do agree with Carl Sagan in that if there is life on Mars then it should not be terraformed, and should be left alone. I don't think we have the right to significantly alter the environment that a unique breed of biology is intricately connected to, at least not right now. Perhaps in the far future when we know just how common or rare life really is then that will change slightly, but I suspect that by that time terraforming will be an irrelevant and unnecessary practice.





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midtskogenDate: Thursday, 14.03.2013, 15:37 | Message # 43
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Comparing the challenges of mining with the challenges of wormhole construction is silly.

Not mining, but mining on asteroids at that scale. The point was more that both are way beyond our current technology. Comparing them makes the "deus ex machina" in the argument of that paper more obvious. Because that is what both are for the paper. "Dei ex machina" to wrap up the loose ends.

Quote (HarbingerDawn)
Ethical dilemmas, the oft ignored dark side of terraforming... so let's discuss them!

I suspect it will be overshadowed by that it is likely going to be politically difficult. If one nation or some nations invest a lot, they need to be sure that someone enjoying the free ride doesn't claim it all, and those who don't yet invest would like not to lose a future claim. In short, the question who will own what will stall radical operations on other worlds even if there is money and will.





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HarbingerDawnDate: Thursday, 14.03.2013, 16:02 | Message # 44
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In short, the question who will own what will stall radical operations on other worlds even if there is money and will.

I disagree, and also this has nothing to do with ethics.





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WatsisnameDate: Thursday, 14.03.2013, 16:12 | Message # 45
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Re: Harbinger:

I think yours is a very good position, and one I agree with wholeheartedly. If life exists on Mars then I think we have no business affecting its evolution, but the unanswered question of how common life is in the universe can complicate this.

The Mars trilogy [here lie minor spoilers maybe] doesn't say much at all about native life on Mars. Rather it revolves around the conflict between people who believe it is okay to terraform Mars to the fullest extent for human habitation (the greens), and those who believe that its original state should be preserved with humans being forced to live under those conditions (the reds). The former favor convenience to humans, while the latter favor minimal impact and natural beauty. I have a very hard time going one way or the other with this, but I (and I hate to say it) think I may lean more toward the green side, mainly as a result of data showing how common planets are.

If Mars is indeed dead (but then again how would we ever know that?) then altering its land and atmosphere don't strike me as major issues considering the vast number of other worlds out there. I.e. I don't have very much objection to converting some of the more easily terraformable worlds to our purposes, while leaving the vast number of other worlds in their pristine state. Again assuming that native life is not a factor here.

A couple related questions for thought:

Would we with current technology be able to unambiguously recognize exoplanets that were 'terraformed' by alien civilizations? (I think this is surprisingly tough to answer).
If we found such worlds, would it affect our views on the ethics? (I don't believe it should.)

Re: Midtskogen:
Quote
The point was more that both are way beyond our current technology. [etc]


Okay, and I understand, but this doesn't change my reaction to it. I think Harb's post #40 summarized my own thoughts very well. But we've talked about this topic pretty thoroughly and I'm not sure if there's much else we can gain from it. I think we should move on.

Quote
I suspect it will be overshadowed by that it is likely going to be politically difficult. If one nation or some nations invest a lot, they need to be sure that someone enjoying the free ride doesn't claim it all, and those who don't yet invest would like not to lose a future claim. In short, the question who will own what will stall radical operations on other worlds even if there is money and will.


Maybe, I don't know. We don't even know what the political/economic situation would be like if/when this occurs. But like Harb said it doesn't have much to do with ethics.

Edit to reply to both of you in one post. smile







Edited by Watsisname - Thursday, 14.03.2013, 16:31
 
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