Cycloidal Ridges on Europa: A Xenoarchaeological Analogue

7 05 2012

Jovian moon Europa. (Credit: NASA NSSDC)

When seriously considering the possibility of xenoarchaeology as a practicable science, I’ve proposed (as have others) the endeavor to be deeply interdisciplinary.

Solid archaeological methodologies will need to be complemented with and modified by a strong foundation in planetary science.

I also often suggest that the practice of xenoarchaeology will find its most frequent utility in “debunking” rushed, biased, or outright pseudoscientific claims.  In many cases, it seems sensible to presume this may appear strictly as planetary science applied in a feature-analysis context.

So, with this in mind, I’d like to look at the mysterious case of “cycloids,” or specifically, “cycloidal ridges” on Jupiter’s second moon, Europa:

Cycloidal double ridges viewed in the northern hemisphere of Europa (60°N, 80°W): Striking evidence that nature can produce apparently-artifical features on other worlds. (Modified from Hoppa et al., 1999)

Jovian Cycloids

Found across both hemispheres of the barren, fractured ice world, these double-ridges are vast – nearly half a mile tall and half-again as wide – and shockingly symmetric, with apparently perfect vertices connecting each sweeping arc.  They exhibit a puzzling nature to parallel nearby ridges, as though “drawn” on the surface of the world in series, yet they then suddenly conflict with ridges curving the opposite direction.

The features were, at the time, truly bizarre, with no understood natural process to account for them.

While due to their immense size and their relatively-obscure nature, no one (to my knowledge) actually suggested them to be the result of Extraterrestrial Intelligence (ETI).

However, due to the cycloids’ striking geometry, I feel them to be a perfect example of an analogue scenario where a scientific xenoarchaeological hypothesis might be entertained.

Still don’t see them?  Look at the features highlighted here in red.

Icy Geoglyphs?

So, let’s say for the sake of argument that a popular case had been made that these were “Europan geoglyphs” – symbols or markers left behind by an ancient extraterrestrial civilization.

While it is often difficult to explain to non-scientists the ultimate importance of seeking to disprove a working hypothesis, in this context the utility of taking such a stance becomes clear.  With any potential xenoarchaeological site or artifact, the first order of business will be to characterize the planetary environment in order to rule out natural causes.  Only then would an archaeological-style investigation proceed, evaluating site context, invoking potential inference-by-analogy, etc.

In the case of Europan Cycloids, given a thorough and persistent site evaluation, a principal xenoarchaeologist, (being interdisciplinary and a capable planetary scientist by necessity,) would have identified that these features could have been caused by tidal forces from Jupiter.  Therefore, the ETI hypothesis is unnecessary, and with no other supporting evidence to suggest the presence of extraterrestrial life, should be refuted.  (To verify the more prosaic explanation from a more archaeological perspective, one might then investigate possible astronomical alignments with respect to the cycloids, [see: archaeoastronomy,] yet these would all point – literally and figuratively – to Jupiter itself, leading to the aforementioned cause.)

Case closed.

Avoiding the Tendency to Cherry-Pick

Why take this approach?  Why be so eager to rule out the “fun” option?  Simple:

In order to challenge the innate predisposition toward bias common to us all, one must work against the preferred hypothesis, not toward it.  (See also: cherry-picking fallacy.)

Now, had the features been discovered on a moon experiencing much less tidal stress, the story might be different…  (One might investigate in-situ geochemistry or seek more up-close imagery to search for detailed evidence of possible machining.)

-But one simply cannot go there first because the implications are possibly thrilling.  It is, in fact, because the ETI hypothesis is fantastic that one must work to rule it out.

This is the fundamental consideration that separates science from pseudoscience, which cannot be overemphasized when proposing something new, (i.e., xenoarchaeology.)


New ideas on the altar of science

23 05 2011
    • How are ideas that had once been considered speculative best adopted into the practice of serious scientific investigation?
    • How are speculative ideas most effectively graduated from the realm of science fiction and introduced into scientific discourse?
    • By what benchmarks of conceptual “distance” are speculative concepts evaluated before being considered too fringe for serious consideration?

A Greek altar to Zeus. (Uncredited)

These are questions with which I find myself (quite unexpectedly, and perhaps, naively,) faced after the publication of my latest article, “A Call for Proactive Xenoarchaeological Guidelines: Scientific, International Policy, and Socio-Political Considerations” in the journal Space Policy.

In it, I discuss the practical realities and considerations necessary to conduct a rigorous investigation of a suspected “alien” artifact – whether conducted on Mars, in orbit, on a returned sample, or around another star.

My logic in writing such an article was straightforward and fairly simple.  With an ever-expanding suite of (primarily robotic) extraterrestrial exploration activities, I argued that it is only a matter of time until we stumble across something we think might be evidence of astrobiological activity (alien life).

Whether or not the suspected site or artifact turns out to be anything special is irrelevant.  The moment we have the suspicion that an item may be of interest is the very instant a preconceived xenoarchaeological methodology becomes useful.  Therefore, we should start thinking about things like xenoarchaeological methodologies ahead of time.

A terrestrial archaeological dig site. (Credit: Lorna Richardson)

After a literature search, it became clear to me that the “scientific endeavor,” (if one could reasonably call it a single thing,) had not yet adequately considered the practical, logistical, and scientific considerations such an investigation would require.  (To the point: when are planetary geologists taught to consider site context from an artifact forensics perspective?  Conversely, when are archaeologists taught to consider different gravity, temperature, pressure, etc., environments in their analyses?)

So, I assembled a general outline based on SETI protocols, COSPAR sample return guidelines, and basic archaeological principles, and I laid it bare upon the altar of science (read: peer review).  I truly believed that it was time to elevate what once existed only in the province of Arthur C. Clarke and Jack McDevitt to serious consideration.

The Apollo 17 field site. (Credit: NASA)

Now, the journal Space Policy is an interdisciplinary journal, which is the level of consideration I was after.  While my first thought was to submit to the journal Astrobiology, the people interested in space exploration concepts at the 40,000-foot-level are the ones I sought to engage rather than the scientists currently entrenched in their own niche work.  I wanted to stimulate the big-picture types to start thinking about what we can and should do in the event of a potential “artifact” discovery by a rover, etc., and to perhaps encourage others to engage and develop these concepts further.

While I received many positive responses and enough constructive feedback to consider the article fruitful, (much of it from astronomers and archaeologists,) not everyone viewed my contribution so favorably.  Chief amongst the opposition turned out to be Dr. Linda Billings, a communications researcher at George Washington University’s School of Media and Public Affairs.  (You can find her blog here).  As it would turn out, she has a longstanding relationship with NASA and has spent decades helping to craft their science message.  Recently, she has been working to promote astrobiology to the public…  and she didn’t like my article one bit.

Mars rover at Victoria Crater, Mars, as seen from orbit. (Credit: HiRISE, MRO, LPL, NASA)

Like a fervent acolyte leaping to the defense of her faith, she plunged an emotionally-charged response straight into the fray.  Clearly, my proposition stepped on some of her conceptual toes.

However, I would argue that when one weighs the immense “deep time” available to exoplanetary systems, the current pursuits of astrobiology and SETI, (which emphasize microbiology and technologically-advanced extraterrestrial life respectively,) leave a gaping conceptual whole where our first physical investigations are actually likely to exist:  An in-situ study of the remains and/or artifacts of extinct alien life.

How would we conduct a rigorous investigation of such artifacts?  What are the pitfalls and likely biases intrinsic to such work?  These are the sorts of questions I sought to spark.

Based on Linda’s failure to address my article’s technical propositions, and considering the fact that she spent the great majority of her time either misstating (or apparently misunderstanding) the article, it seemed almost as though she didn’t really read it.  Instead, it was as though Linda was responding to something I represented to her – perhaps a UFO-hunter seeking to justify sending spacecraft to the “face on Mars” … (which is, after all, just a mesa.)  She preaches semantics at length, (which I argue are inadequate,) and she spends a great deal of time deconstructing arguments my article never made – contradicting herself in the process.  In all, I was quite taken aback, and I was frankly fascinated by the response.  I don’t mind critical feedback, but I would like it to be constructive.

I’m curious if anyone else agrees – she seems to be responding to more than just my article.

As I said earlier, Linda’s response seemed very emotionally-charged to me, and the editor was kind enough to offer me the opportunity to run a counter-response.  (Despite the fact that I was limited by a extremely-confining word count, I was able to address most of her inconsistencies and misstatements in my rejoinder, which ran in the same issue.)

Otherwise, the direct feedback in some circles was positive enough that collaboration has resulted, (in the true spirit of scientific exploration,) and I have a couple of follow-on papers in the works.  In my mind, that’s what this is all about.

In any event, the questions I leave to you are these:

  • When is it too early to begin discussing concepts scientifically?
  • Are we to wait until a discovery and then rush to try and think clearly through the thick of it all?
  • Can and should science be proactive?

We have spacecraft flying all over the place these days.  Personally, I don’t think it’s unreasonable to plan a couple of chess moves ahead.

Who knows?  The effort may just even come in handy.

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