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.)

Advertisements




(Declaration of) Space Independence

6 07 2010

Sean Connery as William O'Niel, a Federal Marshal assigned to a mining outpost on Jupiter's moon Io in the film Outland. Credit: Warner Brothers

Well, being that we recently celebrated Independence Day here in the United States, I’d like to lob a few ideas into the fray regarding the political future of our own activities in space.  Namely, I’d like to talk about the idea of space sovereignty.  “Commercial space” is ramping up, and when thinking seriously about the political realities of working for extended periods of time off-world, practical questions inevitably arise:

  • Under whose laws are astronauts in orbit governed?
  • Who has legal jurisdiction in space?
  • Can laws even be enforced in space when there is no good (or at times even possible) way to police astronauts?
  • Will new or different laws be necessary for the orbital frontier?  For other worlds?
  • Is it a necessary eventuality that those working in space will declare themselves a sovereign “nation” – delivering a new Declaration of Independence from Earth?

Nathan Fillion as post-space-civil-war rebel Captain Malcom Reynolds on the TV series Firefly. Credit: Fox Television

These topics have been addressed fairly extensively in the science-fiction genre.  Popularly, Outland, a film starring Sean Connery in the 1980s, follows a “federal marshal” of sorts whose job it is to maintain the rule of law on the rough-and-tumble mining stations of Jupiter’s moon, Io.  The cult hit Firefly follows a less-than-law-abiding private starship crew eking out an existence in the aftermath of an interplanetary civil war where frontier independence was attempted and failed.  The common themes here recognize that space is truly a frontier, and those who are the first to work there will necessarily be far (the farthest yet!) from those that make and enforce the laws that allegedly govern them.  Obviously this presents problems.  It’s no surprise that these stories tend to fall into the “space western” camp, because perhaps the best parallel human history possesses for how space will be populated is, ahem, how the west was won.

The topic has also been legitimately addressed, at least insofar as it has had to be.  Many people don’t realize that legally today, spacecraft are considered “native soil” of the country that owns them.  The U.S.-owned modules of the International Space Station, for instance, are considered American soil, the Russian-owned modules are Russian soil, and so on.  One can imagine quite a childish scenario should our countries ever declare war, where astronauts and cosmonauts each retreat to their own modules and close the hatches, awaiting their return trip home on separate spacecraft.

U.S.S.R. Cosmonaut Lenov and U.S. Astronaut Stafford meet during the Apollo-Soyuz rendezvous in orbit. Credit: NASA

However, I suspect a little civil disobedience would rule the day in orbit should terrestrial nations with cooperative astronauts ever come into conflict.  The harsh realities of space can only bring into sharp relief human limitations, and as a result, space has historically and consistently been a frontier of cooperation.  Long before the Berlin Wall came down, the ideological and political barriers of the Cold War were surpassed by cooperation in orbit between the United States and the Soviet Union starting with the Apollo-Soyuz program.  This cooperation continued with Shuttle-Mir missions through to the construction of the International Space Station.

Space Shuttle Atlantis connected to Russia's Mir Space Station as photographed by the Mir-19 crew on July 4, 1995. Credit: NASA

Today, the International Space Station itself represents one of the most, (and perhaps the greatest,) globally-cooperative projects in human history, involving 15 nations so far with more in line to participate.  So, I don’t buy that these men and women, who have formed bonds and a working kinship practically impossible for any of us who have not been there to understand, will simply turn their backs on each other because someone on the ground tells them to.

The real wildcards to me in this hypothetical future, however, are the multinational corporations.  What if everything those of us who support “private space” are hoping for succeeds, and private corporations loft their own spacecraft and stations into space?  Well, who’s sovereign soil are those spacecraft?  The country that launched them?  I don’t think that logically follows…  And as I said, if a corporation “resides” and legally operates in more than one nation, is it a free-for-all, like international waters – which would in turn require its own set of laws?

Just a few thoughts.  As always, comments welcome.








%d bloggers like this: