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Life As We (Don't) Know It

Acetonitrile. . .In Space!

You may have seen stories about this paper, which shows that the protoplanetary disk around a (very) young star system is full of HCN, acetonitrile, and other CN-containing compounds. Studies of comets in our own system suggest that these were common materials in our early solar nebula, and this observation strongly suggests that our own situation is not unique. HCN and acetonitrile had already been detected in interstellar dust clouds, but there have been questions about what happens to them during star and planetary system formation. I like how the astronomers call acetonitrile “methyl cyanide” – keep in mind, though, that these are the folks who call everything heavier than helium a metal.
I don’t think that enough people realize just how common the small organic building blocks are around the universe. We already have samples from the carbonaceous chondrites (with the Murchison meteorite being the most spectacular example), full of all sorts of compounds. And many small molecules have been detected in nebulae, with many more surely masked by their spectral characteristics. The universe is soaking in the sorts of molecules that life as we know it uses – and literally soaking in water as well, when you consider how much liquid water and water ice is piled up on the outer moons of our own solar system. All those cheapo science fiction movie plots about aliens coming to Earth to steal our water? No way – the ones where they come to steal Earthly women even make more sense than that idea. I should note in haste that no remotely respectable science fiction author has probably used the steal-our-water trope since roughly the 1930s, but movies are another thing altogether. (Not even The Man Who Fell To Earth made sense to me from that angle, but that was mostly social/political satire, anyway).
So life-as-we-know-it would seem not to have any rate-limiting steps that have to do with getting the starting materials together. The rest of it is still an open question, a big one, but if you also make the reasonable assumption that there’s probably nothing particularly unlikely about our own solar system, life might well be pretty common. (Note that I’m mostly talking about microorganisms, which were, after all, the only form of life on earth for a huge stretch of time. As for intelligent aliens, I refer you to Where Is Everybody?, an excellent book-length treatment of the Fermi Paradox.

21 comments on “Acetonitrile. . .In Space!”

  1. MolecularGeek says:

    IIRC, Asimov did a back-of-the element calculation, and proposed that phosphorus is the element that would be the limiting factor in (potential) terrestrial biomass. Nobody seems to talk much about the relative abundance of phosphine and its ilk in these kind of studies.

  2. RM says:

    Yes, but Earth’s water is naturally occurring and biodynamic. Space water is dead and filled with toxic chemicals like acetonitrile and cyanide.
    We’re safe as long as the aliens haven’t been reading Food Babe.

  3. The Iron Chemist says:

    So you’re saying that I won’t need to construct a Pacific Rim-style robot to protect my organic solvents if we make contact with alien life?

  4. That Guy says:

    ‘I should note in haste that no remotely respectable science fiction author has probably used the steal-our-water trope since roughly the 1930s, but movies are another thing altogether.’
    Unfortunately Hollywood has demonstrated time and again that it is replete with pretty faces, but not much imagination. For a recent example of said trope, see ‘Oblivion’ starring Tom Cruise and Andrea Riseborough.

  5. robbbbbb says:

    There is a very sensible explanation for the Fermi Paradox:

  6. postoc in space says:

    I’m quite surprised there were so much stories about this paper. As astrochemists, we have been reproducing formation pathways of this species since the 80s, and the question was not “will it?” but “when?”.
    The largest organic in space is, to date, HC11N (excluding C60 and C70), part of polyyne family. From what we have seen, this family is extremely reactive, especially at low temperature, as they are able to form even under heavy UV flux.
    Where do we find these? Everywhere, but our instruments are biased toward them because of their permanent dipole moment.
    Our dear Woon (famous in our small field) maintains an updated list of species detected in various regions of space at (rule 1 is: no asking about the website design).
    By the way, the real question in the field right now is “how do we form those damn aromatic cycles”, and there were some controversies recently about direct benzene from acetylene fragments or fulvene.
    We are still trying to find some real glycine but I don’t really question its existence in space, just the previous detection.

  7. steve says:

    I don’t know why you’re making such a big deal about a few carbon-based molecules flying around in outer space when Spock clearly showed that the Horta on Janus VI are silicon-based. We must eschew our carbon-based lifeform provincialism.

  8. steve says:

    And, of course, there is no such thing as the Fermi Paradox, it’s just that advanced civilizations follow the Prime Directive, as necessitated by the Federation.

  9. MoMo says:

    Dont forget the interstellar ethanol clouds.
    Proof that God wanted us to have alcohol.

  10. Paul D. says:

    We should really, REALLY want there to be no ET life. If life arises easily, and complex life too, then that’s probably the worst news the human race will ever receive. It would mean the “Great Filter” that apparently prevents intelligent species from colonizing the galaxy is in our future, not in our past.

  11. Derek Lowe says:

    #10 Paul – or they’re ferociously advanced and incomprehensible, to the point that our culture would not survive contact. . .

  12. Sebastian A says:

    It is interesting you post this just around the time this article is published in the print edition of Nature Chemistry
    The Sutherland lab has shown you can get precursors to biomolecules from essentially hydrogen cyanide, forming a type of proto-metabolism.

  13. milkshake says:

    “…keep in mind, though, that these are the folks who call everything heavier than helium a metal.”
    Planetary scientists also call “ices” any white frozen material with a melting point between -200 and + 200C, including such things like methane, ammonia, carbon dioxide, and even nitrogen

  14. milkshake says:

    @10: One does not really need alien – installed filters to prevent galaxy colonization. The limits imposed by physics suffice. It is not even completely clear if humans can make it to Mars and back, without getting sick and sterile.

  15. Gordonjcp says:

    So with space being all full of water and big greasy hydrocarbons, does that mean we need to be worried about aliens coming to steal all our cat litter?

  16. Morten G says:

    It took our planet more than 3 billion years to be “terraformed” to the point of sustaining multicellular life. Somehow without turning into a snowball or hot, dense soup. Universe is only about 13 billion years old. We could simply be first.
    If we weren’t first I would have expected the planet to have been sterilized by a Berserker von Neumann probe long ago. Of course that doesn’t mean that we can’t still filter ourselves out later on.

  17. steve says:

    #16 – Your argument is rendered unlikely by the vast numbers of stars. The idea that we’re the only planet among the likely trillions of similar planets ( on which multicellular life evolved is highly improbable. And that just covers biology similar to ours, not including the possibility of other chemistries evolving into self-replicating organisms.

  18. Postide says:

    @14: We’ve been exploring space for, what, fifty years now? Give humanity a few millennia before judging. 🙂 A kid who just learned how to float in the wading pool without drowning isn’t going to be crossing the English Channel anytime soon – but give her time. (Or put her on a boat, or chunnel.)
    …not to downplay the insane problem that is interstellar travel, nor the equal parts confusion and horror that is the Fermi Paradox.
    @1: We shouldn’t be worried about phosphorus limitations; I’m sure aliens will all just use arsenic. 😉

  19. Secondaire says:

    Well, there won’t be too many aliens coming to earth if they have to fly through the big cloud of cyanide on the way in…

  20. Paul D. says:

    The idea that we’re the only planet among the likely trillions of similar planets ( on which multicellular life evolved is highly improbable.
    If you know this, you must know the probability that life will arise (and the mechanism, so you can estimate that probability). So when do you pick up your Nobel Prize?

  21. dave w says:

    #20: we at least know that the probability is non-zero (n>=1 in maybe trillions), even if we don’t know the full mechanism by which we originated. (The error bars on “n” would be too huge to falsify the statement that n>1…)

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