Field of Science

A good paper, but is it 'astrobiology'?

A while back I asked for examples of good astrobiology papers.  After a bit of back-and-forth with some commenters, I clarified my search:  I was looking for papers that reported competent experimental research and self-identify as 'astrobiology'.  And I was looking for personal recommendations to papers that had been read by the person recommending them, not just pointers to journals or reports where I could read astrobiology papers and decide for myself whether they were any good.

The results were disappointing.  The problem wasn't that the commenters recommended papers that turned out to be lousy, but that they didn't recommended any recent papers at all, except for a reanalysis of Miller's original spark-discharge material from his 1953 experiment.  The problem wasn't that the commenters were ignorant of the field - one was the Director of the NASA Astrobiology Institute, who directed me to a recent report on the Institute's success but didn't give personal recommendations for any of the publications it lists.

I'm thinking about this issue now because of a paper that just appeared in PNAS, titled Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases (authors Callahan et al.).  CNN's Lightyears blog headlines this as DNA discovered in meteorites, but most reports were more sensible.  (The image below is from the Lightyears blog.)

To my non-expert eye this looks like good science.  The results are not really surprising (purines have been found in meteorites before), but they're very solid.  What makes this work important is that the authors surveyed a wide range of meteorites, carefully eliminated sources of external contamination with terrestrial purines, and showed that the distribution of purines found in the meteorites matched that produced by laboratory reactions simulating space chemistry but not that of terrestrial contaminants (e.g. they found not only the common terrestrial contaminant adenine but also 2,6-diaminopurine).

So is this good paper a good astrobiology paper?  I don't think it qualifies.  Although most of the authors are supported by NASA, they nowhere mention astrobiology or consider whether their work has implications for the origins of life anywhere but on Earth.  

(I'm officially a zoologist, so now I'm off to the San Francisco Zoo, planning to be back in time for the SciFoo meet and greet this afternoon.)


  1. Utterly perplexing! Isn't this like asking for papers that self-identify as "environmental science" (say)?

    Astrobiology is also an integrative discipline*, it has regular courses, it gets money for research and it is unfortunately regularly abused both by internal (press & funding) and external (media & political) forces.

    Asking for self-identification won't work outside of those disciplines that regularly do so. This fallacy of prediction means that you can read anything into your hypothesis.

    Perhaps that is you intention, making the line of questioning more understandable. Otherwise, better would be to ask the general question on science: what use is astrobiology? It concentrate resources on research, it interest students and it engages the public. I don't know of a better test for science.

    [Disclaimer: I have studied astrobiology at the nearest university.]

    * What you learn from astrobiology text books is that Earth is the type case we know about. Which means that perhaps 99 % of the discipline is outright non-astrobiology. (I haven't done a paper survey, it's a throw out guess.)

  2. This is crazy! Of course it is an astrobiology paper, do you put a note in your papers saying "A disclaimer: This is a microbiology paper"?

  3. NotAnAstrobiologistAugust 12, 2011 at 7:43 PM

    I'd have to say this is an unequivocally an astrobiology paper, the NAI is clearly cited as a funding source for 4 of the 8 authors. The subject matter is also certainly related to objectives as defined by Astrobiology (as defined by NAI).

    I'm certain I could find papers in journals with words like "Astronomy", "Computer Science" or "Biochemistry" that don't actually have the subject name occur in the paper; but are clearly fall under the accepted scope of the subject as named.

    I was frustrated though in some previous posts where the comments' authors seemed to want to usurp everything ever done under the astrobiology banner.

    Watson and Crick...Astrobiology...seriously? The discovery of Archea? C'mon. In both of those cases the link is clearly post-hoc.

  4. NotAnAstrobiologistAugust 12, 2011 at 8:13 PM


    [I'm certain I could find papers in journals with names that have words like "Astronomy", "Computer Science" or "Biochemistry" in the journal title, that don't actually have the subject name occur in the paper; but are clearly fall under the accepted scope of the subject as named.]

  5. Astrobiology does cover the relationship of life on earth to space. If we wanted to get bogged down in terminology, We could call this paper Astrobiochemistry.

  6. Dr. Redfield,

    This is precisely why myself and other suggested you look at overview documents for the field. Anyone that has read the Astrobiology Roadmap or the Astrobiology Primer can clearly see where this fits into the field.

    More specifically, within the astrobiology primer, Objective 3.1 states:
    Objective 3.1—Sources of prebiotic materials and catalysts. Characterize the exogenous and endogenous sources of matter (organic and inorganic) for potentially habitable environments in the Solar System and in other planetary and protoplanetary systems.

    Clearly, this paper follows objective 3.1.

    Within the astrobiology primer, there is a subsection entitled "Comets and meteorites as sources of organic compounds."

    ...and if that were not enough, in the very paper astrobiology and exobiology are repeatedly acknowledged for providing support:

    "K.E.S. acknowledges support from the Goddard Center for Astrobiology. M.P.C., J.C.S., D.P.G., and J.P.D. acknowledge funding support from the NASA Astrobiology Institute and the Goddard Center for Astrobiology and the NASA Astrobiology: Exobiology and Evolutionary Biology Program."

    But wait! There's more!

    The authors also self-identify as being members of astrobiology organizations in their affiliations:
    "aNational Aeronautics and Space Administration Goddard Space Flight Center and The Goddard Center for Astrobiology, Greenbelt, MD 20771; bDepartment of Geosciences and Penn State Astrobiology Research Center, Pennsylvania State University, 220 Deike Building, University Park, PA 16802; cGeophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015; and dScientific Instruments Division, Thermo Fisher Scientific, Somerset, NJ 08873"

    So this is a paper that follows on the stated objectives of the field, speaks to a topic on which an overview document has a subsection, specifically and repeatedly calls out astrobiology funding sources, AND under author affiliations lists astrobiology organizations.

    Upon what sensible criteria is this even a question?

  7. I don't see any biology in this paper. Only organic chemistry.

  8. Anon, no one is claiming it is a biology paper. The question that has been asked is whether or not it is astrobiology, which is not biology nor a subset thereof.

  9. NotAnAstrobiologistAugust 13, 2011 at 2:17 PM

    Eep. This is turning into a name game that no one can win.

    We can all play the card that says all biology is just physics anyway, so why do we call it that?

    Someone got a big pile of money together and doling it out to people who are (broadly) doing things that have to do with finding life in contexts outside of earth. Yes, the name is a bit misleading, since we haven't found any concrete evidence that life exists outside earth. A large part of the work was funded under that banner and has scientific merit, it is useful to refer to it as astrobiology.

    I think 'useful' is the key here; no one can really win an argument based on 'should'.


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