# Alien steel **URL:** \ **Category:** Factual Questions\ **Created:** [July 28, 2013, 10:05am UTC](https://boards.straightdope.com/t/alien-steel/664729 "2013-07-28T10:05:09Z")\ **Posts on this page:** 14\ **Page:** 3
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [August 5, 2013, 12:17pm UTC](https://boards.straightdope.com/t/alien-steel/664729/41 "2013-08-05T12:17:33Z")
> [@aNewLeaf](#): > > No oxygen, no plant life, no soil, no mineable ores. So why colonize there?. It has lots of potential. You’re indirectly pointing out that Earth is very special. Humans have evolved to live on it and life has made it a very convenient place in many ways. Even planets with life will not be anywhere near as good. As far as the time for cyanobacteria to raise oxygen to breathable levels in the planet, all you have to do is look at the [Great Oxygenation Event](http://en.wikipedia.org/wiki/Great_Oxygenation_Event) of our own planet. It took something like 1.5 billion years between the first production of oxygen and when it got to something we could breath. Now it should not take that long for this new planet. Early cyanobacteria were not as productive as they are currently (photosynthesis took a while to evolve to its current state) plus there’s humans to help things along in various ways. But it’s still going to be long in terms of human life. > [@Reply](#): > > Hydro may be as affordable as it is only with Earth’s level of preexisting infrastructure (unlimited labor pool, ability to industrially produce massive amounts of concrete, ability to divert rivers and move huge amounts of dirt, etc.) So you’re saying that it took a lot of coolies to build Grand Coolee Dam? > [@](#): > > . Geothermal seems more conceivable for a small colony with a small labor pool but advanced technology and the ability to choose a landing site. Oh, and plain ol’ nuclear might be an option too if you think of it in terms of potential energy per unit of cargo weight carried by their spacecraft? Geothermal sounds good, but note they won’t be able to choose just any place in the planet. They want to locate their spaceport (and hence their first settlement) fairly close to the equator, say within a couple thousand kilometers of it. Plus they want a large sheltered bay nearby. ---
**Author:** ![aNewLeaf](https://avatars.discourse-cdn.com/v4/letter/a/ac91a4/32.png) [@aNewLeaf](https://boards.straightdope.com/u/aNewLeaf)\ **Post date:** [August 5, 2013, 12:30pm UTC](https://boards.straightdope.com/t/alien-steel/664729/42 "2013-08-05T12:30:13Z")
“potential” So, in the universe you are describing, planets are uncommon, and good ones are rare.? We can’t simply choose a better planet, this is the best opportunity we are going to have? In that case, I think seeding with microorganisms and waiting will be a key part of the process. Give it 500 years, maybe a thousand, then come back to a place that has oxygen, plant life, and other usable resources. And if you are going to take a millennium to terraform a planet, you might as well start with Mars. No need to go to other solar systems, we’ve got crapsack worlds with potential right here at home. Mars, some of the Jovian moons, maybe Venus too. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [August 5, 2013, 1:38pm UTC](https://boards.straightdope.com/t/alien-steel/664729/43 "2013-08-05T13:38:30Z")
> [@dtilque](#): > > As far as the time for cyanobacteria to raise oxygen to breathable levels in the planet, all you have to do is look at the [Great Oxygenation Event](http://en.wikipedia.org/wiki/Great_Oxygenation_Event) of our own planet. It took something like 1.5 billion years between the first production of oxygen and when it got to something we could breath. Now it should not take that long for this new planet. And there were undoubtedly predators, which would not be the case in this scenario. From that article: > [@Wiki](#): > > For example, at today’s rates of photosynthesis (which are much greater than those in the land-plant-free Precambrian), modern atmospheric O2 levels could be produced in around 2,000 years. Now add in a lack of predation and we have something happening in a usably short space of time. Still many generations, though. But neither Mars nor Venus have any potential for life at the moment. Venus is too near the Sun and doesn’t have a significant magnetic field and Mars is insufficiently massive and cold and inert to boot. Now, if you were to swap Venus and Mars, and put Triton around Venus to give it a rapid rotation and thus a magnetic field, and bombard it with ice from Triton, and manage to not change the orbit of the Earth, then you might have something. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [August 5, 2013, 2:10pm UTC](https://boards.straightdope.com/t/alien-steel/664729/44 "2013-08-05T14:10:03Z")
> [@the\_diego](#): > > So I’m not the only one who fantasizes about developing a planet surface beginning from just bare rock, water and CO2-N2. I wonder why people like thinking about this? Because when you design a world soup to nuts you can work around the need for things like spiders. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [August 6, 2013, 10:15am UTC](https://boards.straightdope.com/t/alien-steel/664729/45 "2013-08-06T10:15:04Z")
> [@aNewLeaf](#): > > “potential” > > So, in the universe you are describing, planets are uncommon, and good ones are rare.? > We can’t simply choose a better planet, this is the best opportunity we are going to have? No. Earth-like planets are common and almost all of them that have liquid water already have life on them. This is a rare one where, for some reason, life never developed. Life-bearing planets have their own set of problems. With a lifeless planet, you can immediately start terraforming. > [@](#): > > In that case, I think seeding with microorganisms and waiting will be a key part of the process. They want to push things along faster than microorganisms would do on their own. That requires a human presence on the planet. > [@](#): > > And if you are going to take a millennium to terraform a planet, you might as well start with Mars. > No need to go to other solar systems, we’ve got crapsack worlds with potential right here at home. Mars, some of the Jovian moons, maybe Venus too. Mars will be a crapsack world even after terraforming. For one thing, it’ll still be cold. This other planet you can wear shirtsleeves from the start, as long as you have an oxygen supply. It also has a magnetic field, which Mars lacks. > [@Quartz](#): > > And there were undoubtedly predators, which would not be the case in this scenario. From that article: > > > [@Wiki](#): > > > > Wiki > > For example, at today’s rates of photosynthesis (which are much greater than those in the land-plant-free Precambrian), modern atmospheric O2 levels could be produced in around 2,000 years. > > Now add in a lack of predation and we have something happening in a usably short space of time. Still many generations, though. I don’t think a lack of predation will make much difference. For one thing, even if you manage to seed the planet with only cyanobacteria, evolution will inevitably result in non-photosynthesizing organisms developing sooner or later. These will be either predators or parasites or more likely, some of each, but in any case, will slow the oxygenation down. But that 2000 year figure comes from taking the total amount of oxygen in the atmosphere and dividing by the amount of oxygen all the plants on Earth produce in a year. It doesn’t take into account the oxygen sinks that made the Great Oxygenation Event take so long. Those sinks (dissolved metals in the ocean and unoxygenated rocks on land) will be present on this other world. > [@The Great Sun Jester](#): > > Because when you design a world soup to nuts you can work around the need for things like spiders. Spiders are an important part of the ecology; they aren’t going to be left out of this new world. A number of useless parasites will not be included, though. I think the reason why lifeless planets are popular for this kind of exercise is that existing life on a planet creates difficulties. Mainly, how is the alien life going to interact with any introduced Earth life? This is a problem too complex for a single person to tackle on his own. ---
**Author:** ![aNewLeaf](https://avatars.discourse-cdn.com/v4/letter/a/ac91a4/32.png) [@aNewLeaf](https://boards.straightdope.com/u/aNewLeaf)\ **Post date:** [August 6, 2013, 11:16am UTC](https://boards.straightdope.com/t/alien-steel/664729/46 "2013-08-06T11:16:38Z")
Well I don’t know where to go with this. You’ve deliberately picked a planet that will be hard to do anything with, then you’ve shot down every idea anyone has had. It seems you’ve written yourself into a corner from which there is no good escape- you’ve got to invent a technology or construct some other deus ex machina. As for the spider issue, Robert Heinlein addresses that and some of the other challenges that would be involved in his novel _Farmer In the Sky_. Everybody interested in terraforming, or gardening Earthside, should read it, it’s a classic for a reason. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [August 6, 2013, 12:31pm UTC](https://boards.straightdope.com/t/alien-steel/664729/47 "2013-08-06T12:31:32Z")
> [@dtilque](#): > > I don’t think a lack of predation will make much difference. For one thing, even if you manage to seed the planet with only cyanobacteria, evolution will inevitably result in non-photosynthesizing organisms developing sooner or later. These will be either predators or parasites or more likely, some of each, but in any case, will slow the oxygenation down. Neither are likely to evolve in any meaningful timescale. Humans aren’t going to wait the millions of years that such evolution would be expected to require. Hell, I doubt we’d be willing to wait even a thousand years. About a hundred years is probably the limit - people will know that their grandchildren will benefit. > [@](#): > > But that 2000 year figure comes from taking the total amount of oxygen in the atmosphere and dividing by the amount of oxygen all the plants on Earth produce in a year. It doesn’t take into account the oxygen sinks that made the Great Oxygenation Event take so long. Those sinks (dissolved metals in the ocean and unoxygenated rocks on land) will be present on this other world. So what? It doesn’t account for the extra oxygen that would be generated if there were no herbivores either. And anyway, you’re postulating a planet like modern Earth so the rampant vulcanism of the early Earth is absent, so the oxygen sinks would not be renewed. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [August 6, 2013, 4:33pm UTC](https://boards.straightdope.com/t/alien-steel/664729/48 "2013-08-06T16:33:18Z")
> [@](#): > > No. Earth-like planets are common and almost all of them that have liquid water already have life on them. This is a rare one where, for some reason, life never developed. Life-bearing planets have their own set of problems. With a lifeless planet, you can immediately start terraforming I agree that planets that already have life on them will have their own set of problems; the life on a alien world is quite likely to be unpalatable, inedible, allergenic or actively toxic to a human. We might prefer to eradicate much, or most of the biosphere before we can live there comfortably; this might cause some problems with conservationists, if any survive into the galactic imperial era. But I doubt very much that life is as common as you have depicted, especially complex life. We don’t know how often abiogenesis occurs, and it may be rare, very rare or vanishingly rare. Even in a (fictional or speculative) universe where life occurs on almost every Earth-like planet, the fraction of those with complex metazoan life might be quite small. Our own planet, for example, will probably only have complex metazoan life for about a billion years or so, out of a probable existence of ten billion years in total. If Earth is typical we might expect to find complex multicellular life on about one in ten worlds. In my opinion your supposedly ‘inhospitable’ world is in fact one of the most hospitable of all possible types of terrestrial world - other worlds will be too hot, too cold, have too much greenhouse effect, be too massive or not massive enough, have too rapid or too slow a spin, have an extreme or unstable obliquity, include toxic elements in the lithosphere, hydrosphere and/or atmosphere, and/or possess toxic, voracious, allergenic or just plain inedible lifeforms. Compared to those options, your planet is positively welcoming. Martyn Fogg, who wrote _Terraforming: Engineering Planetary Environments_, has proposed a classification of Earth-like planets that divide them into **Habitable** worlds that require no modification for human habitation, **Biocompatible** planets that may have a complex biosphere, and **Easily Terraformable** planets that are lifeless but can be modified into habitable worlds quite easily. Habitable worlds are probably vanishingly rare, Biocompatible planets may have inimical biospheres that are a danger or inconvenience to the settlers, so the third class, into which your hypothetical world seems to fall, are likely to be the most useful of all, and we should think ourselves lucky if we find any of this sort within a few tens of light years of Earth. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [August 6, 2013, 7:14pm UTC](https://boards.straightdope.com/t/alien-steel/664729/49 "2013-08-06T19:14:27Z")
In my list of reasons why an Earth-like planet might not be comfortable, I forgot to include the eccentricity of the orbit, the frequency of cometary bombardment, the presence or absence of a magnetic field, perturbations from nearby planets and other objects, the variability of the star and the strength of its stellar wind; … not to mention the UV flux from the local star and any other unwelcome radiation from nearby stars or objects. There is a whole planetary zoo out there, and we have barely begun to consider all the possibilities. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [August 6, 2013, 7:27pm UTC](https://boards.straightdope.com/t/alien-steel/664729/50 "2013-08-06T19:27:44Z")
> [@dtilque](#): > > Spiders are an important part of the ecology; they aren’t going to be left out of this new world. A number of useless parasites will not be included, though. Arguably ‘useless parasites’ which keep immune systems fresh and help eliminate organisms evolving toward nonhardiness are no less fundamental to an ecosystem than spideys. I’m just sayin, pretty much anything a spider eats can be eliminated or turned into some kind of creation that hasn’t adjusted its fecundity to account for spider predation, and from the other direction, something much less horrific than spiders can be created to do what spiders do. Hell, you could make a critter that looks like a fingernail sized kitten to go after spider food, I’d be all for that. 8 fucking eyes, 8 super creepy legs, venom that dissolves prey from the inside, and a nasty stalking walk is simply evidence of a malevolent god. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [August 6, 2013, 9:12pm UTC](https://boards.straightdope.com/t/alien-steel/664729/51 "2013-08-06T21:12:03Z")
> [@The Great Sun Jester](#): > > I’d be all for that. 8 fucking eyes, 8 super creepy legs, venom that dissolves prey from the inside, and a nasty stalking walk is simply evidence of a malevolent god. Or an early terraforming attempt gone wrong. Maybe the cyanobacteria blossoms will bring the DREAD INTERGALACTIC SPIDERS out of hypnosleep… duh duh duh. No amount of iron will save them now. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [August 6, 2013, 9:28pm UTC](https://boards.straightdope.com/t/alien-steel/664729/52 "2013-08-06T21:28:31Z")
Which is why all terraforming projects need to have orbiting space stations that can nuke the planet from orbit. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [August 7, 2013, 12:51am UTC](https://boards.straightdope.com/t/alien-steel/664729/53 "2013-08-07T00:51:11Z")
> [@The Great Sun Jester](#): > > Which is why all terraforming projects need to have orbiting space stations that can nuke the planet from orbit. That’s really not a bad idea. If the colonists don’t push a button every 30 days, the entire planet gets nuked to prevent the spread of whatever it is that killed them. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [August 8, 2013, 12:21pm UTC](https://boards.straightdope.com/t/alien-steel/664729/54 "2013-08-08T12:21:51Z")
> [@aNewLeaf](#): > > Well I don’t know where to go with this. > You’ve deliberately picked a planet that will be hard to do anything with, then you’ve shot down every idea anyone has had. > It seems you’ve written yourself into a corner from which there is no good escape- you’ve got to invent a technology or construct some other deus ex machina. Huh? I don’t know where you get this idea. The OP was about how metals could be made in an oxygenless and fossil-fuel-less world. There were several decent ideas in the first dozen or so answers. I just have to pick one that seems to require the least investment by the colonists. I suspect you’re probably responding to the discussion about how long it will be before the atmosphere is breathable. As far as I can tell, this is going to be a very long time, perhaps 10,000 years, even with help from the colonists. That’s a very small fraction of the time it took Earth to gain a breathable atmosphere, but I expect you’re going to be unhappy with it anyway. > [@eburacum45](#): > > Our own planet, for example, will probably only have complex metazoan life for about a billion years or so, out of a probable existence of ten billion years in total. If Earth is typical we might expect to find complex multicellular life on about one in ten worlds. I don’t think Earth is typical in that way. Our planet will become uninhabiable in about half a billion years because the Sun will warm up faster than the Earth recedes from the Sun. But there are more stars that are lower mass than the Sun. Even ignoring M-type dwarfs, there are more K and G3-G9 stars than there are G2 or higher (i.e. more massive). These less massive stars will heat up more slowly, so there will be a longer time that an Earth-like planet around them will be inhabitable. That said, there will be a sizable percentage (probably more than half) of planets that have life but it’s either single-cell only or multi-cellular but just oceanic. > [@](#): > > In my opinion your supposedly ‘inhospitable’ world is in fact one of the most hospitable of all possible types of terrestrial world - other worlds will be too hot, too cold, have too much greenhouse effect, be too massive or not massive enough, have too rapid or too slow a spin, have an extreme or unstable obliquity, include toxic elements in the lithosphere, hydrosphere and/or atmosphere, and/or possess toxic, voracious, allergenic or just plain inedible lifeforms. > > Compared to those options, your planet is positively welcoming. I agree. I’m not the one who characterized it as “crapsack”. > [@](#): > > Martyn Fogg, who wrote _Terraforming: Engineering Planetary Environments_, has proposed a classification of Earth-like planets that divide them into **Habitable** worlds that require no modification for human habitation, **Biocompatible** planets that may have a complex biosphere, and **Easily Terraformable** planets that are lifeless but can be modified into habitable worlds quite easily. > > Habitable worlds are probably vanishingly rare, Biocompatible planets may have inimical biospheres that are a danger or inconvenience to the settlers, so the third class, into which your hypothetical world seems to fall, are likely to be the most useful of all, and we should think ourselves lucky if we find any of this sort within a few tens of light years of Earth. Agreed also. This world is not close to Earth. I haven’t decided how far away, but at least 100 ly and possible more than double that. I wouldn’t expect there to be any **Habitable** planets (as defined above) anywhere in the entire galaxy. If there’s alien life, chances of there being some kind of negative interaction between lifeforms of the our biosphere and another are great. Just think of the many millions of types of bacteria in each. Are all of them going to play nice with the alien lifeforms? > [@Quartz](#): > > > [@dtilque](#): > > > > I don’t think a lack of predation will make much difference. For one thing, even if you manage to seed the planet with only cyanobacteria, evolution will inevitably result in non-photosynthesizing organisms developing sooner or later. These will be either predators or parasites or more likely, some of each, but in any case, will slow the oxygenation down > > Neither are likely to evolve in any meaningful timescale. Humans aren’t going to wait the millions of years that such evolution would be expected to require. Hell, I doubt we’d be willing to wait even a thousand years. About a hundred years is probably the limit - people will know that their grandchildren will benefit. I don’t think you understand how quickly evolution occurs among single-cell organisms, especially when there are empty niches available. Seeding the planet with just cyanobacteria leaves many, many niches unfilled. I would expect at least some of them to be filled in a very short time, pehaps just a few years. So you may as well introduce a full marine micro-ecology in the first place. It’ll be more balanced than just one species. And after all, the idea of terraforming this world is to create a second Earth biosphere. Might as well get it started correctly in the ocean. [Previous page](https://boards.straightdope.com/t/alien-steel/664729.md?page=2)