Wednesday, November 28, 2012

Guessing about Curiosity's Discovery - Viking Redeemed


Sample Analysis at Mars for Curiosity (SAM)
Sample Analysis at Mars for Curiosity
Whatever the big Mars news NASA is sitting on is, it seems be related to measurements made by Curiosity's Sample Analysis at Mars (SAM) instrument, which is tasked to search for compounds containing carbon. According to NASA's description, "because these compounds are essential to life as we know it, their relative abundances will be an essential piece of information for evaluating whether Mars could have supported life in the past or present."

This would suggest that NASA is prepared to report the presence of organic compounds in the samples scooped up from "a patch of dusty sand called Rocknest." The implication here being that active biological processes may be at work in what is an arbitrary and, from all appearances, not particularly hospitable piece of Martian real estate.

Five Bites Into Mars at Rocknest
Not only would this be a momentous finding, but it would also redeem the "discovery" made by the Viking landers in 1976. Those pioneering Mars probes detected much the same thing. Their conclusion was initially celebrated, later dismissed and only resurrected as a possible valid result in the last half-dozen years.

So the question for me is why has Greg Webster, a Jet Propulsion Laboratory spokesman - although it appears he has been dispatched from NASA's Department of Expectation Reduction - said that the findings would be "interesting" rather than "earthshaking"? My guess is two-fold.

Having been already burned by the early indication of the detection of methane, which turned out to likely be a stowaway gas brought along from Cape Canaveral, NASA wants to hedge its bets. Although the sample gathering apparatus aboard Curiosity had been deliberately purged of Earthly contaminants by an initial dry run using Martian soil, it's sort of remarkable that a first sample should yield such dramatic results.

The startling possibility here is that not only is life present on Mars, but that it is pretty much everywhere. A theme from the song "New York, New York" comes to mind: if you can make it there, you can make it anywhere. That's life.

Carl Sagan with Viking model
But I think that the primary challenge for NASA, and one reason for the backpedalling, is that, as with the Viking results, many people, including the public at large, are not going to find indirect evidence of life there that persuasive. They aren't expecting to see little green men, but they are expecting to see little green microbes.

Fittingly, it was Carl Sagan, a prime mover behind Viking, who reminded us that extraordinary claims require extraordinary evidence. But he left us on our own to figure out what exactly qualifies as extraordinary evidence.

Creative Commons License
Guessing about Curiosity's Discovery - Viking Redeemed by Marc Merlin is licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License.
Based on a work at http://thoughtsarise.blogspot.com/2012/11/guessing-about-curiositys-discovery.html.
Post a Comment