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NASA

What Silicon-Based Life Might Be Like 92

Posted by timothy
from the would-want-totally-different-cable-channels dept.
Nancy_A writes "While the world as we know it runs on carbon, science fiction's long flirtation with silicon-based life has spawned a familiar catchphrase: 'It's life, but not as we know it.' Although non-carbon based life is a very long shot, this Q&A with one of the U.S.'s top astrochemists — Max Bernstein, the Research Lead of the Science Mission Directorate at NASA headquarters in Washington,D.C. — discusses what silicon life might be like."
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What Silicon-Based Life Might Be Like

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  • Easy (Score:5, Funny)

    by ericloewe (2129490) on Sunday December 04, 2011 @07:03AM (#38256298)
    A large clump of silicon that lays eggs and produces and extremely corrosive acid to chew through rock.
    • Re:Easy (Score:5, Informative)

      by Snard (61584) <.moc.liamg. .ta. .kulawahs.ekim.> on Sunday December 04, 2011 @07:17AM (#38256336) Homepage

      For those who don't get the reference: http://en.wikipedia.org/wiki/Horta_(Star_Trek) [wikipedia.org]

    • NO KILL I

      And they'll also have a tenuous grasp of English grammar, at best.

    • Re:Easy (Score:5, Funny)

      by 3vi1 (544505) on Sunday December 04, 2011 @08:36AM (#38256588) Homepage Journal

      I'm a doctor, not a bricklayer!

    • Yea,straight out of Star Trek TOS(Devil In The Dark) The Horta was such a creature.If you follow the timeline placed by the books,1 served aboard the Enterprise as an assistant science officer.He could munch a rock sample and give you a readout of what it was made of,like a gourmet describing a good meal..
      Sci-fi aside,isn't there a deep water crab from the Pacific that is silicon based?(the blue crab).I remember reading about this odd critter quite a few years ago.

      • All known life on earth is carbon based*. Exoskeletons are made using multiple minerals depending on species and biome but that doesn't imply that we have aragonite-based life forms.

        *Theoretical shadow biospheres notwithstanding.
      • Re:Easy (Score:5, Insightful)

        by meerling (1487879) on Sunday December 04, 2011 @01:20PM (#38258468)
        We have a lot of divergent lifeforms from what was taught when I was little.
        They used to say nothing could survive in the vacuum of space, the bottom of the ocean, in geysers, highly acidic conditions and so many other places. If they knew about the oceanic geothermal vents (like the black smokers) back then, they'd have sworn they would be lifeless.
        Now of course, we have the entire category of Extremophiles that live in those very places and conditions.

        Additionally, we have lifeforms that have copper based blood instead of iron, ones that respire sulfur instead oxygen, and diatoms build their skeletons/shells/cell walls out of silica. And now they may have found one that exchanges its phospates for deadly arsenic and lives.

        All in all, there are significant portions of life on this world that was considered science fiction several decades ago. Does that mean it's possible that life in other parts of the universe can be very different than ours? Sort of. It means that our understanding of what is necessary for life is incomplete due to our exposure to only our own type of biology. There may be very strange biochemistry out there, but most of it that we might recognize as life will probably be similar to ours. (That's the biochemistry, not the form, or if intelligent, culture.)
    • Re:Easy (Score:5, Interesting)

      by Runaway1956 (1322357) on Sunday December 04, 2011 @09:23AM (#38256776) Homepage Journal

      What's funny about attempts to visualize other types of life forms is, we tend to visualize those life forms in our own environmental terms. That is, we tend to assume some basic atmospheric conditions, pressure ranges, and temperature ranges. We "assume" certain basic conditions that resemble our own conditions.

      Silicone? How about we break the cycle by trying to visualize silicone under hundreds of thousands of tons of pressure, and thousands of degrees, with and atmosphere of ammonia? Or, alternatively, in a vacuum at tens of thousands of degrees? Partial pressure atmospheres at near 0 degrees kelvin?

      Of course, the question arises then, how and why are mankind interacting with such creatures under such conditions?

      Of course, I was enamored with the idea of "living rock" as I child. Some story I read mentioned it, and I had the idea that some rock was really alive. Of course, it isn't - or IS IT?!?!? Nothing says that we are smart enough to recognize alien life when we see it. Geologic time and man's time are so different, that we might not even recognize that a rock actually breathes, or moves, or reproduces. Again, let's step outside our own familiar conditions. Assuming that time might be entirely different for some other life form in conditions that are inimical to us, why would we hang around long enough to collect the data necessary to determine that this or that rock really is alive?

      I certainly don't have any answers about the existence of life outside our own experience. But, it amuses me to see the almost idiotic assumptions that people make when considering and debating the possibility. “It’s life, but not as we know it” How about the possibility that a face to face meeting with another life form might be fatal to one or both of the participants in the meeting? His environment is a poisonous atmosphere (to me) and my own body radiating heat might be fatal to him!

      • Actually... (Score:5, Interesting)

        by denzacar (181829) on Sunday December 04, 2011 @10:06AM (#38256950) Journal

        How about we break the cycle by trying to visualize silicone under hundreds of thousands of tons of pressure, and thousands of degrees, with and atmosphere of ammonia? Or, alternatively, in a vacuum at tens of thousands of degrees? Partial pressure atmospheres at near 0 degrees kelvin?

        Max Bernstein mentions something very similar to that in TFA.

        Dorminey â" DO YOU THINK THAT SILICON-BASED LIFE MIGHT EXIST SOMEWHERE OUT THERE?

        Bernstein â" Maybe deep below the surface of a planet in some very hot hydrogen-rich, Oxygen-poor environment, you would have this complex silane chemistry. There, maybe silanes would form reversible silicon bonds with selenium or tellurium.

         
         

        How about the possibility that a face to face meeting with another life form might be fatal to one or both of the participants in the meeting? His environment is a poisonous atmosphere (to me) and my own body radiating heat might be fatal to him!

        A biochemist's vision of such an encounter, for your listening pleasure. [youtube.com]

      • by Anonymous Coward

        The two assumptions that I see most often are these: that other life will function on similar time scales to us (which you mention), and that it will exist on similar spatial scales to us (i.e., big enough for us to see, small enough to notice us). What if life existed as, say, self-replicating patterns of magnetic turbulence in the lobes of radio galaxies, with each organism being thousands of light-years across? Or as microscopic agglomerations of nuclei in the condensed matter on the surface of a neutr

      • by Anonymous Coward

        "Silicone"? Sorry, can't take your post seriously, or be bothered to read it, if you cannot distinguish between a compound and an element.

      • We "assume" certain basic conditions that resemble our own conditions. Silicone?

        Like Pamela Anderson, you mean?

      • What's funny about attempts to visualize other types of life forms is, we tend to visualize those life forms in our own environmental terms. That is, we tend to assume some basic atmospheric conditions, pressure ranges, and temperature ranges. We "assume" certain basic conditions that resemble our own conditions.

        There's little to no point in imagining alien life if you can't get with it, Captain Kirk-style, and everyone knows that.

      • Stephen Bakster's trilogy referenced stone flowers that bloom once in a thousand years on the moon, or something of the sort.
  • by Anonymous Coward

    .. on there talking about pre-conditions.

    As RNA may have been a pre-condition to DNA, carbon-based life could very well be the pre-condition for silicon-based life.
    Life doesn't need to come about naturally, there is no universal definition, if it happens it happens.

    Silicon life forms may actually need to be designed by intelligence because of how hard it is to get a stable start up in environments. It could be some sort of really rare form of life due to the energies required.
    Likewise that case of arsenic

    • by houghi (78078)

      Silicon life forms may actually need to be designed by intelligence because of how hard it is to get a stable start up in environments.

      That is what many religions say about life in general.

      • The difference is, religions typically believe their "creator was, and always has been". OP (I believe) realizes that humans evolved without a "divine touch" and is talking about a possible next step in evolution. Just because "nature" doesn't make it happen, doesn't make it any less significant. We are a product of nature and evolution after all.
    • by Rei (128717) on Sunday December 04, 2011 @08:15AM (#38256522) Homepage

      The problem is of people envisioning silicon-based life in a manner that's too similar to carbon-based life. Silicon life, if ever found, is essentially guaranteed to not have any long Si-Si-Si-.... chains; they're not stable. The silicon equivalent in terms of stability is Si-O-Si-O-Si-O... etc (silicone). Silicon also has some fascinating complex chemistry in the form of silanols, which can form membranes, catalysts, and all sorts of other fascinating stuff [ic.ac.uk]... so long as they don't get too hot or in too acidic or basic of a chemical environment.

      • by tuxicle (996538)

        so long as they don't get too hot or in too acidic or basic of a chemical environment.

        Isn't this also true of carbon-based proteins (usually what membranes and catalysts are made of)?

  • by papar (893096) on Sunday December 04, 2011 @07:21AM (#38256354)
    I love it how Dorminey IS CONSTANTLY YELLING HIS QUESTIONS AT BERNSTEIN. Oh good God I can't even get this post past Slashdots caps filters!
  • If the Gadmeer and Sekkari are any indication, non-carbon-based life seems to have really bad luck. At least they were smart enough to send out seed ships. http://stargate-sg1-solutions.com/wiki/Gadmeer [stargate-s...utions.com] http://stargate.wikia.com/wiki/Gadmeer [wikia.com] http://stargate.wikia.com/wiki/Sekkari [wikia.com]
  • Why not here? (Score:5, Informative)

    by vlm (69642) on Sunday December 04, 2011 @07:47AM (#38256436)

    Why not evolve Si life here?

    Dorminey — WHERE ARE THE LARGEST CONCENTRATIONS OF SILICON HERE?
    IN SAND?

    Bernstein — In sand or rock. There are literally megatons of silicate minerals on Earth.

    Talk to a geologist like my ex roommate. I knew there was something fishy about that so I checked the actual numbers:

    http://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth's_crust [wikipedia.org]

    Silicon 277200 ppm second only to oxygen
    Carbon 300 ppm second to pretty much everything but vanadium and stuff like that. By weight the earth has about as much Rb as C.

    For all intents and purposes the earth is not the idea place for a carbon based life form. Its the equivalent of a unit train full of high fructose corn syrup tank cars for a silicon lifeform. If they can't form here and absolutely gorge themselves on what to them would be the equivalent of a giant pizza, there is not a more ideal place out there to form...

    The reason why we're made out of relatively rare C instead of tremendously available Si is C chemistry is incredibly better than Si chemistry for bio, or heck, chemistry in general. The fine article didn't give it enough justice or maybe the editors edited out the chemistry rants. Lets just say that Xe biochem is not all that more unlikely or difficult than Si biochem would be (in other words, nearly totally freaking almost incomprehendibly impossible vs just merely incredibly extremely impossibly unlikely)

    It all has an air of speculative fantasy fiction, like trying to intellectually debate if its easier to make vampires, werewolves, or zombies...

    • Re:Why not here? (Score:5, Informative)

      by meglon (1001833) on Sunday December 04, 2011 @07:55AM (#38256458)
      Better yet, talk to an organic chemist. First day of organic our prof detailed why silicon based life is a non-starter. Make chains of carbon and you get such an incredible variety of things that they make up over half the compounds known; make chains of silicon and you get: more sand.
      • Re:Why not here? (Score:5, Interesting)

        by Rei (128717) on Sunday December 04, 2011 @08:04AM (#38256486) Homepage

        There's more ways to form a complex compound than just Si-Si-Si-Si... chains (which, as you note, tend to oxidize into crystaline silicon dioxide). As a random example as proof, look at silica gel. Si-O-Si-O-Si-O... etc. Chain it pretty much as long as you want, functionalize the side chains, etc.

        When it comes to LNAWKI (Life Not As We Know It), I think a lot of people lack creativity to a tremendous degree -- envisioning the situation as altering only one parameter (say, substituting silicon for carbon but otherwise keeping the chemical structures roughly the same).

        • Re: (Score:2, Interesting)

          by Anonymous Coward

          OK, I would concede the general point that it somewhat depends on how one defines "life", but I would still argue that the grandparent posts are largely correct:

          As noted above, the fact remains that Si - Si bonding is much weaker than C - C bonding due to the relative positions of these elements in the periodic table, which means that any kinds of polymerized molecular species that you might want to try to kick off life with still probably wouldn't last as long in a primordial environment as their carbon-ba

          • Long Si-O-Si-O chains are all through the mineral kingdom, forming chains, linked chains, sheets, 3-D cages, and I don't know what else.

            Worried that the bonds are too stable? Evolve it in a hotter environment.

          • Re:Why not here? (Score:4, Informative)

            by polymeris (902231) on Sunday December 04, 2011 @05:18PM (#38260298)

            where you get silicon & oxygen in sufficient quantities

            Everywhere on the earth's crust? [wikipedia.org]

            I don't actually understand enough about the chemistry of Si & C to make a direct comparison, but regarding the issue of bonding strength you mention, wouldn't other factors, like temperature and pressure affect this? Possibly even making Si-based life fitter for some environments?

          • by Rei (128717)

            As noted above, the fact remains that Si - Si bonding is much weaker than C - C bonding

            Which is why silicon-based life would primarily use Si-O chains instead of C-C chains, as previously mentioned. Once again, you reinforce my main point: most people are way too uncreative, only looking at a direct C/Si substitution, which isn't at all realistic. You want to talk stability? Bake cookies on a plastic sheet sheet, then bake them on a silicone baking sheet, and tell me which survives the ordeal better.

            Thin

        • by meglon (1001833)
          Unfortunately, imagination isn't the issue, chemistry is. Silicon simply doesn't do what carbon does when it forms bonds. Substituting silicon into place of carbon chains would not yield molecules that do the same thing, act the same way, or even look the same (silicon is a much larger atom).
          • by Rei (128717)

            Which is the whole point: we're not talking about a direct substitution. Your argument is like saying "Java programs can't exist, because if you substitute a line of C code in a C program with a line of Java code, the program breaks."

            • by meglon (1001833)
              Actually, it has to be a direct substitution. Carbon is the backbone of the molecules in ours, and every living thing on the planets, bodies. Carbon is it.. it's the skeleton all the other stuff gets attached to carbon, and only carbon. There isn't a mixture of a few carbon based molecules here, a few silicon based molecules there, a few boron based molecules over that direction... just carbon; and there is a very specific reason for that.

              My argument is a lot less like substituting a line of code into
              • by Rei (128717)

                Carbon is the backbone of the molecules in ours, and every living thing on the planets, bodies

                In *ours* and every living thing that evolved from primitive carbon-based organism on *Earth*'s bodies. We're not talking about life on Earth. We're talking about xenobiology. You're arguing from a dataset of precisely one element. The question is not what is life on Earth like, but whether all life must be like it is on Earth.

                My argument is a lot less like substituting a line of code into a program of a diffe

        • Its all in the ability to store information with the least decay in this multidimensional universe. The quantum geometry of carbon has no equal.
      • Re:Why not here? (Score:5, Informative)

        by sFurbo (1361249) on Sunday December 04, 2011 @08:22AM (#38256538)
        No, you don't get sand. The silicon equivalent of organic compounds are polysilanes, not polysiloxanes. Making them seems to have been a rather popular niche in the 70's. However, they are unstable, as Si can form more then 4 bonds, so isomerisation is much more rapid than with carbon.

        The reason 90 % of the known compounds are organic is because a) there is amble supply different carbon-based compounds to manipulate, as life has made sure, and b) they are more interesting as pharmaceuticals then inorganics. Based on pure chemistry, boron is nearly as versatile as carbon, but starting blocks for boron chemistry is harder to come by, as is funding.
        • Based on pure chemistry, boron is nearly as versatile as carbon, but starting blocks for boron chemistry is harder to come by, as is funding.

          Sulfur is another candidate often cited for its bonding capabilities.

    • Re:Why not here? (Score:5, Insightful)

      by thomst (1640045) on Sunday December 04, 2011 @08:14AM (#38256518) Homepage

      vlm answered the musical question:

      Why not evolve Si life here?

      Thusly:>/p>

      Carbon 300 ppm second to pretty much everything but vanadium and stuff like that. For all intents and purposes the earth is not the idea place for a carbon based life form.

      Incorrect, I'm afraid.

      If you exclusively look at the abundance of carbon in the Earth's makeup, you miss the most crucial aspect of hydrocarbon-based biochemistry: the abundance of water as a solvent for hydrocarbons, particularly here on the surface of the planet, where the incredible profusion of possible compound-producing reactions benefits tremendously from sunlight as a source of energy input to trigger the making and breaking of hydrocarbon bonds.

      A world where carbon is greatly more abundant - but water is largely absent - wouldn't necessarily be more conducive to the evolution of life.

      The reason why we're made out of relatively rare C instead of tremendously available Si is C chemistry is incredibly better than Si chemistry for bio, or heck, chemistry in general. The fine article didn't give it enough justice or maybe the editors edited out the chemistry rants. Lets just say that Xe biochem is not all that more unlikely or difficult than Si biochem would be (in other words, nearly totally freaking almost incomprehendibly impossible vs just merely incredibly extremely impossibly unlikely)

      This, on the other hand, is a much better point ... and, IMnsHO, one deserving of an "Insightful" upmod.

    • by TeknoHog (164938)

      The reason why we're made out of relatively rare C instead of tremendously available Si is C chemistry is incredibly better than Si chemistry for bio, or heck, chemistry in general. The fine article didn't give it enough justice or maybe the editors edited out the chemistry rants. Lets just say that Xe biochem is not all that more unlikely or difficult than Si biochem would be (in other words, nearly totally freaking almost incomprehendibly impossible vs just merely incredibly extremely impossibly unlikely)

      One explanation I've heard is simply that silicon atoms are larger than carbon. Thus there is more space to attack the bonds. For example, in SiH_4 the hydrogen atoms are further apart, compared to CH_4. The technical explanation probably involves the variety of orbitals as well, since carbon only has s and p, but silicon also has d orbitals, again making the attack space bigger.

    • by Anonymous Coward

      For all intents and purposes the earth is not the idea place for a carbon based life form. Its the equivalent of a unit train full of high fructose corn syrup tank cars for a silicon lifeform. If they can't form here and absolutely gorge themselves on what to them would be the equivalent of a giant pizza, there is not a more ideal place out there to form...

      Assuming, incorrectly, that complex, silicon-based chemistry works well within...
      a) in the presence of later amounts of water
      b) in the presence of free atmospheric oxygen at Earth temperatures
      c) at a wide variety of pH ranges, including the common neutral pH of water.

      It turns out that none of these are true. Earth is an absolutely horrible place for silicon-based life, if it's even possible. If silicon-based life uses oxygen-based respiration, its by-product is a solid at Earth temperatures. Water reacts

    • by joshamania (32599)

      Though not proof, I think your reasoning is sound. I've begun to wonder whether or not DNA isn't a fluke any more than say, carbon monoxide, or water, or methane. Molecules have specific ways...finite ways...in which they can form...one cannot just make up new bonds and create crazy random molecules. DNA follows the rules. Why wouldn't it exist elsewhere?

    • by surd1618 (1878068)
      I dunno. I think that the oxygen content is the issue, more than the abundance of silicon. Perhaps on a planet where all of the oxygen is tied up in iron or aluminum, silicon could make some complex chemistry with sulfur, phosphorus, and/or other elements. And why not life primarily made of silicon that extensively uses carbon, like carbon life extensively uses phosphorus?

      I do think that carbon-based life that dwells in ammonia and carbon dioxide is more likely than silicon-based life, but I don't think t
  • Mammals? (Score:5, Funny)

    by TeknoHog (164938) on Sunday December 04, 2011 @07:50AM (#38256444) Homepage Journal
    They better be mammals, otherwise all those nice silicon-based polymers are udderly wasted.
  • by Hognoxious (631665)

    Sort of like a white spiky coral that kills everyone unless they hide in a cave with an android.

    It can be killed with music.

  • by Anonymous Coward

    Just wondering.

    • by Anonymous Coward

      Just wondering.

      Why? You mean to tell me that they're speculating on the mere possibility of silicon-based life......and already you want to fuck it?

      Jesus...

    • Slightly above the chair you're sitting on.
  • by allo (1728082) on Sunday December 04, 2011 @08:43AM (#38256626)

    will believe the universe only exists since 1.1.1970.

  • Stupid rocks (Score:5, Insightful)

    by sgt scrub (869860) <saintium.yahoo@com> on Sunday December 04, 2011 @09:05AM (#38256700)

    There should have been a question like "is there an environment that might make it more plausible for Silicon life"? What about planets that are molten or have oceans, lakes, and rivers of acid. Why would an intelligent rock walk around in place where they will become immobile? Sounds like something only dumb rocks would do.

    • by Anonymous Coward

      Why would an intelligent rock walk around in place where they will become immobile? Sounds like something only dumb rocks would do.

      Most plants are relatively immobile but you wouldn't call a tree dumb would you? I mean I probably have called one dumb but it's usually me being dumb and walking into one of them.

  • by Anonymous Coward

    "Honey? When did your boobs start talking?"

  • Hmm (Score:2, Insightful)

    by lightknight (213164)

    Interesting. Though I am curious why Silicon life hasn't already evolved on the Earth.

    Think about it. There isn't necessarily a reason why Silicon / Carbon / other-based lifeforms can't all evolve in the same environment. There's no law, save those of Physics / Chemistry / etc., that says that if you have one, you cannot have the other.

    So, why is earth filled with only Carbon-based lifeforms (to our knowledge)? Perhaps there is something poisonous about our planet, with regards to Silicon lifeforms, such th

  • I would imagine it was hard to respond to questions calmly and intelligently when THEY WERE ALL SHOUTED AT HIM by Dorminey.

  • Real life is NOT based on your computer and its silicon chips. Real life is in the outside world, away from your computer!

    • Real life is NOT based on your computer and its silicon chips. Real life is in the outside world, away from your computer!

      How would we know?

  • Disadvantages of exhaling silica dust: many. Advantages of exhaling silica dust: possible abrasive for lapping processor die, as well as immunity to the dreaded pneumonoultramicroscopicsilicovolcanoconiosis.
  • by mbone (558574) on Sunday December 04, 2011 @01:50PM (#38258678)

    If you think about it, the people claiming that advanced civilizations would create self-replicating Von Neumann machines that would spread throughout the galaxy, are really claiming that carbon-based life would create (and maybe be supplanted by) silicon-based life. In the same way that RNA-life may have been necessary to get to DNA-based life, carbon-based life may be a necessary pre-condition for silicon based life. (We might think of those Von Neumann machines as robotic spacecraft, but those that can evolve would likely supplant those that cannot, and in a few billion years take on forms that we cannot predict.)

  • They would have Carbone breast implants.
  • by uvajed_ekil (914487) on Sunday December 04, 2011 @07:38PM (#38261456)

    Although non-carbon based life is a very long shot...

    Isn't this a really big assumption? Sure, we haven't seen any non carbon-based life, but we also haven't found carbon-based life on more than one little planet.

  • A dialogue with apologies to Terry Bisson
    Shamefully adapted From "Alien/Nation" in the April 1991 issue of Omni Magazine.

    "They're made out of silicon."

    "silicon?"

    "silicon. They're made out of silicon."

    "silicon?"

    "There's no doubt about it. We picked several from different parts of the planet, took them aboard our recon vessels, probed them all the way through. They're completely silicon."

    "That's impossible. What about the radio signals? The messages to the stars."

    "They use the radio waves to

  • We're all staring that the beginnings of silicon-based life right now.

Our policy is, when in doubt, do the right thing. -- Roy L. Ash, ex-president, Litton Industries

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