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.)





Xenoarchaeology: Reality and Fantasy

3 05 2012

Archaeological evidence of extraterrestrial involvement with ancient human civilizations, as seen in the movie, “Prometheus.” (Credit: Fox)

Cultural Xenoarchaeology

For reasons I can’t immediately explain, (the recent rash of technical publications addressing the concept of “xenoarchaeology” or “non-terrestrial artifacts” nonwithstanding,) there is a tantalizing idea cropping up in a number of recent and upcoming films and television programs.  (See: Indiana Jones and the Kingdom of the Crystal Skull, Prometheus, Ancient Aliens.)

This concept, simply, involves the discovery of archaic evidence of the existence of Extraterrestrial Intelligence (ETI) and/or evidence of physical interactions of ETI in Earth’s (and mankind’s) past.  All of this, arguably, might be lumped under the auspices of the protoscience Xenoarchaeology.

Perhaps this increase in popular consumption of the idea that aliens have been around longer than we have indicates a mounting social awareness of cosmic deep time and the possibility of extraterrestrial life as it is stirred together with our classic, collective existential questions: “Why are we here?” and, “Are we alone in the universe?”

However, these pop-culture expressions and depictions of xenoarchaeology stray pretty far afield of what “scientific xenoarchaeology” would actually look like.

Separating Xenoarchaeology Fiction from Fact

In most part built upon ideas originally popularized by Erich von Daniken decades ago, (and fictionally by H.P. Lovecraft before him,) these modern concepts invoke the assistance of ETI in the development of human civilization as the “gods” of the religions and mythologies of antiquity.  However, this view has long since been shown by archaeologists to be entirely speculative and lacking in any direct, physical supportive evidence, (i.e., it is pseudoarchaeology.)  This stands in contrast to the physical archaeological evidence that does exist to directly support the idea that we humans created civilization, agriculture, the pyramids, etc., without need of assistance.

While the idea of meddlesome, elder-brother or mentor-type ETI is admittedly thrilling, the concept as it relates to xenoarchaeology does not automatically become scientific and in fact differs significantly from the groundwork currently being laid out for scientific xenoarchaeology.

Allow me to provide a few examples of where reality and fantasy diverge:

  • The practice of much fictional xenoarchaeology takes place on Earth, whereas future scientific xenoarchaeologists will likely find their skills of most utility on other worlds during in situ investigations.
  • Fictional/pseudoscientific xenoarchaeology typically centers on terrestrial features of human civilization, (e.g., pyramids, temples, large-scale geoglyphs,) whereas proposed xenoarchaeological investigations will likely center on extraterrestrial features of a possible artificial nature on other worlds.
  • Fictional xenoarchaeology usually assumes the involvement of ETI with a given feature of interest and works from there, whereas scientific xenoarchaeology will be required to rule out all other natural planetary, biological, and geological possibilities before hypothesizing ETI.  (In fact, ruling out features as xenoarchaeological in nature and disproving those making pseuarchaeological claims will probably be the most frequent uses of the existence of a true, scientific practice of xenoarchaeology.)
  • Xenoarchaeologists of popular fiction conduct investigations with their bare hands, whereas scientific xenoarchaeologists will primarily use remote sensing techniques, (satellites, robotic rovers,) to investigate/collect data.  (Or, if they are very lucky, they might one day even conduct work from within a spacesuit or biological quarantine facility.)
  • Fictional xenoarchaeology attempts to find evidence of ETI in terrestrial archaeological sites or artifacts, whereas scientific xenoarchaeology will rely on the fact that ETI was not involved in terrestrial archaeological sites and artifacts in order to construct relationships and methodologies that will be useful in the evaluation of a potential site of completely alien/unknown character. 

I could go on, but hopefully the potential difference between xenoarchaeological reality and fantasy, (like popular depictions of most sciences,) has been made clear.

Why Xenoarchaeology at All?

When considering the concept of scientific xenoarchaeology, invariably the question arises: “Is there a need for xenoarchaeology as a science at all?” 

Admittedly, this question is a good one.  Pseudoscience aside, there are currently no pressing sites of xenoarchaeological interest.  Why, then, expend the effort?

Well, let me first point you to the established field of astrobiology.  This is a field devoted entirely to the origin, evolution, and possibility of extraterrestrial life.  Associated with the field are multiple related academic journals, societies, and even college degree programs. 

Astrobiology is legitimate.  Yet, we have yet to discover even the smallest extraterrestrial microorganism.  Yes – Astrobiology, the scientific study of alien life, is currently conducted in spite of the complete absence of the known existence of alien life.  The field thrives regardless.  Why?

Astrobiology thrives because its underlying assumptions are viewed to be scientifically sound.  Life occurred on Earth, and considering the pantheon of worlds being discovered around other stars, by all modern physical and biochemical reckoning, signs seem to point that it will only be a matter of time until we discover life elsewhere.  (By similar reasoning, the Search for Extraterrestrial Intelligence [SETI] continues its vigilant watch for technological [radio] signs of life in the galaxy, and few nowadays write off the pursuit as being in vain.)

The assumptions underlying the scientific development of xenoarchaeology are, indeed, indentical to those above.  And further, given the ambiguity of the term “intelligence” and modern knowledge of many cosmic threats that can cause mass extinctions, (novas, gamma-ray bursts, asteroid impacts, etc.,) it seems even more likely that material evidence of extinct extraterrestrial life will be encountered prior to the fortuitious discovery of life itself while it is still alive. 

That is, if I were a gambling man, I would wager that xenoarchaeologists get an opportunity to evaluate ultimately definitive evidence of extraterrestrial life prior to astrobiologists.

Xenoarchaeological Relevance

In the final analysis, popular depictions of xenoarchaeology are useful in that they engender a more sophisticated (if not completely sensationalized) view of our place in the cosmos and the possibility of intelligent life in it.  On the technical side, considering the current absence of evidence of extraterrestrial life, xenoarchaeology as a scientific pursuit is equally justifiable to astrobiology and SETI. 

Further, I would argue that like astrobiology, taking the time to rigorously conceptualize a scientific field tangential to those that exist but centered in an extraterrestrial context will help us see ourselves from a clearer scientific vantage; this will invariably serve to enhance our understanding of terrestrial archaeology, anthropology, biology, and yes, even astrobiology.  (Developing an additional means to address some of the planetary pseudoscience out there, e.g., Martian Cydonia, can’t hurt, either.)

And who knows?  Perhaps our space exploration investigations are only a rover or two away from the discovery of that first Martian or Titanean burrow or petroglyph, which history will remember as a moment that literally changes everything. 

My view is that it’d be far better in the event of such a discovery to be proactive and have scientific xenoarchaeology prepared, (in at least a cursory sense,) instead of being reactive and leaving the scientific establishment scrambling to catch up. 

In this sense, perhaps science could stand to learn a thing or two from Hollywood.








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