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Arsenic and the life extraterrestrial

Last updated on 22 Jun 2018

Paul Z. Myers, a little known biologist from Minnesota has published a lovely debunking of the hype surrounding the “second life” announcement from NASA. He should do more science-related posts. He’s really good at them. Here are some other excellent pieces: Bytesized Biology, Leaf Warbler, Greg Laden; Wired; and Ed Yong.

I do wonder why NASA saw fit to do this, or perhaps Science did; either way it’s very bad for science. It pumps up interest among the aficionados only to disappoint them when the claims are seen to be overblown. Surely it is significant enough that we find that arsenides can replace phosphates; it’s not earth-shattering, though, especially since it was the researchers who evolved this from prior dispositions of the extremophilic bacteria. Hell, Andy Ellington at U Texas has been evolving non-standard biochemistries for years.

Perhaps it has something to do with the present Congressional moves about NASA; I don’t know. But like the Darwinius furore, it helps nobody promote science.

However, I wanted to note something amusing. PZ has this snippet of the periodic table:


Notice that Arsenic (As) is in the same column as Phosphorus (P) which it will replace in crucial biochemical structures and pathways due to a similarity of valency. Notice that next to it is Selenium (Se)? Remember this? In an otherwise ridiculous plot[1], the protagonist for the movie Evolution notices that the arrangement of the chemistry of the aliens is like ours except that instead of having an oxygen-based chemistry they have a nitrogen-based one, and he infers that since arsenic is poisonous to us, selenium, a primary component of Head and Shoulders shampoo, would be poisonous to them.

Art precedes, well, life…

  1. Julianne Moore would fall for David Duchovny? Before she fell for me? Really?


  1. On a similar note, I seem to recall an episode of the X-Files which had a Silicon- rather than Carbon-based life-form.

    And really, shouldn’t it have been Germanium that would be poisonous? I mean, come on, it’s sloppy science like that that let down the whole movie…

    • John S. Wilkins John S. Wilkins

      Product placement…

    • Ian H Spedding FCD Ian H Spedding FCD

      Star Trek beat X-Files on this one. Remember the Original Series episode The Devil in the Dark with the Horta which burrow through solid rock as easily as we walk through air? Notable for one of Dr McCoy’s famous disclaimers. When asked to treat the injuries of a creature made largely of stone he protests “I’m a doctor, not a bricklayer!”

  2. John Monfries John Monfries

    Echoes of the Darwinius hype…

    But when did Julianne Moore fall for you? This is a part of the Wilkins life we haven’t previously heard of.

    • John S. Wilkins John S. Wilkins

      I live in hope…

    • Didn’t you know that the reason the Albino Aussie Anthropoid has no time to blog is that he is too busy fighting off Holywood beauties who want to bury their hands in his luxuriant fur.

  3. Ian H Spedding FCD Ian H Spedding FCD

    At least we know the silver in the silverback is not due to dandruff.

    And I liked Evolution. I thought it was very silly and very funny.

    The film, that is, not the theory.

    Actually, I have to mention in this context that, whenever I see one the usual photographs of Darwin, I’m reminded of the epic film Gettysburg. One reviewer felt it was disappointing in most respects but did display the most impressive display of luxuriant facial hair ever assembled for a Hollywood movie.

  4. Clem Stanyon Clem Stanyon

    I liked Evolution, too (sorry, don’t know italics HTML tag)…but the real problem was that the aliens’ chemistry should have been F-based; the gag was about anti-dandruff shampoo being toxic (if the smell and colour wasn’t enough of a clue, don’t ever even taste that stuff!!).

    I’ve wondered why we are designated a Carbon-based life form, when the principal components of our chemistry are H, C, N and O… NOCH-life for the party people, or HONC if you’re carbon-based? Why pick on Carbon; it’s not as if there are any silicon-based life forms of which we are aware from which to distinguish our kind of life…or is it?

  5. Jon Wilkins Jon Wilkins

    This strikes me as a public-goods situation. This and the Darwinius nonsense are just extreme versions of what goes on all the time with the “gene for X” and “new hope for curing cancer” spins that constipate so much science journalism. I think the problem is that there are short-term benefits to the scientists and journalists who exploit these tactics. The negative consequences tend to be more diffuse, and accrue over longer timescales. Typically, this will be in the form of a general cynicism and skepticism towards science on the part of the general public.

    Unfortunately, these negative consequences fall back on the science community as a whole, rather than on the perpetrators of exaggeration. What is typically needed in these situations is a system of reputation and/or punishment. In some contexts, this can happen organically, but I’m not sure that this is one of those contexts.

    As for Julianne Moore, maybe she could be lured in by a provocatively worded press release.

  6. Argon Argon

    Actually it’s true that PZ is little known… in the overall field of biology. Outside of biology he has a much larger name.

    That’s OK.

    Note however that nitrogen, above phosphorous in the periodic table is a pretty lousy substitute for the latter in most biomolecules. Arsenic is also pretty bad overall. There are some processes that may accept the substitutions with less impact on viability, but not many.

  7. Bob O'H Bob O'H

    Ah bum, they really should have used Ar for arsenic (as it’s left of selenium on the periodic table).

  8. I wasn’t repelled by the hype in the article. Since absolutely all popular science reporting is hyped, I unconsciously filter out the exclamation marks and overstated generalizations as I read such things. I guess I assume that others wear the same anti-glare sunglasses as I do. Anyhow, absent the stupid, the gist of the research was still very impressive and that’s what registered with me. I was particularly taken with the possibility that these organisms use ATA in lieu of ATP to energize themselves. (As a guy who constantly deals with scientific papers in my day job, I also operate with the default that no single paper ever established a damn thing; but that’s a somewhat different issue. Just which basic molecules replace the phosphorous with arsenic remains to be seen, as even the New York Times article grudgingly admitted.)

  9. Molly dfley Molly dfley

    I like the creative thought behind this relative study of Arsenic and Extraterrestrial objects, which I never see happening in the near future (no pun intended to Science).

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