Wednesday, January 21, 2009

Titan: Why the Huygens probe probably won't - sadly - tell us much

In "World's Most Advanced Inter-planetary Probe Meets Biology's Greatest Conundrum," Robert Deyes discusses the Huygens probe of the Saturnian moon Titan, aimed at discovering how life came to exist on Earth:

And yet while the initial photographs of Titan had unveiled a methane sea complete with its own islands and coastline (Ref 16), we were still a long way from obtaining even a sketch of how life might have arisen on our own planet. Rather than being a 'golden spike' event as biologists Christopher Wills and Jeffrey Bada might have hoped for, in which primordialists and evolutionists finally united the animate with the inanimate world (Ref 17) , the landing of the Huygens probe served only to widen the chasm between simple organic compounds and complex biotic polymers. After all, the methane lakes, canals and open seas on Titan that had initially generated so much euphoria, provided no clues as to how the simplest biochemical processes might have arisen or even as to how a primitive membrane, needed to separate such processes from the damaging and disruptive forces of the surrounding environment (Ref 18), might have been formed.
And anyway,

Natural selection needs something to select, something that is already functional. To appeal to chance as an alternative and to thereby assume that the random assembly of nucleotides and amino acids could generate functional strings of information-rich code is to appeal to the miraculous.

Even before Huygens landed, astrobiologists were adamant that whatever was found on the surface of Titan it would not be "life as we know it" (Ref 21). Such a statement should not be allowed to steer us away from the fundamental conundrum of life's origins- that is, how the genetic instructions that form the blueprint for the existence of every organism on earth simply emerged. Science journalist Denyse O'Leary sent a cautionary note to those eager to formulate an answer, warning of "the risk of seeing things that are not really there, because we want them to be there so badly" (Ref 22). We should take stock of O'Leary's words and follow the evidence wherever it leads. That applies as much to origin-of-life studies as it does to any other field of science.
Deyes is kind to quote me as he has. The main thing to see here is that finding life on another planet (or moon) may - or may not - shed light on how life came to exist on Earth. Of course we would love to know, and rightly so. But there is a genuine danger of reading too much into the things we do find.