(Playing The Martian Guessing Game - Addendum #1)
Now this is unusual:
NASA has taken the extraordinary step of issuing a 2nd strong denial in a formal press release Thursday afternoon (11/29/12) and tamped down expectation of any major news announcements at Monday's American Geophysical Union (AGU) meeting in San Francsco. In an unequivocal statement, NASA said there will be no LGM (Little Green Men) on Monday.
Of the scientists and reputable science bloggers who have stuck their necks out to hypothesize what the Curiosity rover has discovered (myself included), all agree the most likely new result is organic chemistry, specifically hydrocarbons. This makes the latest NASA statement:
"Rumors and speculation that there are major new findings from the mission at this early stage are incorrect... At this point in the mission, the instruments on the rover have not detected any definitive evidence of Martian organics."
... sound like quite the spoiler to all our careful, inductive reasoning. Yesterday the New York Times had NASA's JPL spokesman saying:
"... that a really big announcement, if one should occur, would most likely be made at NASA headquarters in Washington and not at an academic conference"
Which you would think to be true... the last big LGM announcement in 1996 had President Bill Clinton join his science advisor and the NASA administrator to wax philosophically about just one Martian meteorite found in Antarctica. Over the next few years, ALH 84001 was examined by more researchers and that "major discovery" turned out to be chock full of doubtful claims.
Today's NASA press release follows a concerted effort to drive the mainstream media to squash the hype and lower expectations. On the other hand, 16 years after ALH 84001 became the temporary media darling, I believe both NASA and President No-Drama Obama know to leave any major announcement short of living, laser-packing, little-green-men to an academic conference.
NPR's Joe Palca, after starting the Martian Guessing Game last week, must be sweating little green bullets by now. I respect Palca's science reporting and am sympathetic to his situation. I think he heard exactly what he reported and saw at least a raised eyebrow on Dr. Grotzinger's countenance to stick his neck out as he did. I'm going to stick with making guesses too, even if it requires me to parse the NASA press release with the dexterity of Bill Clinton defining sex.
As I stated, outside scientists and science writers have almost uniformly come out believing the MSL Curiosity found organic chemistry, i.e. hydrocarbons. Other scientists have pointed out that organics in Martian surface materials should not be found, due to the destruction of hydrocarbons by UV and ionizing radiation. Indeed, hard radiation plus lots of time conspire against easily finding organics. This is well-reasoned conjecture, yet the in situ data will carry the day. If organics from ancient life exist, then the low temperatures along with chelating iron and clay compounds may provide suitable protection. Only by touching and tasting can we really find out.
That's exactly what the SAM instrument suite was designed to find. How does it work? Martian dust is carefully sieved, then placed in quartz cups and heated to as much as 1000 deg. C. Any compound that is volatile is released as a gas and carried with inert helium to the three instruments which can identify the evolved compounds. Now, as was beautifully demonstrated in 1987 by physicist Phillip Morrison with the help of his neighbor Julia Child, any carbon compounds heated to a mere 200 deg C. will eventually pyrolize to pure carbon (do check it out! [youtube http://www.youtube.com/watch?v=iw-cZhTISBk). expand=1] By design, the evolved gases in the SAM instruments have been thermochemically decomposed, i.e. larger carbon molecules become smaller fragments the instruments can identify. The gas chromatograph separates and measures the time it takes each molecular species to diffuse through a dense medium, which is indicative of size and shape (larger, longer carbon chains pass slower); each species can then be passed into the mass spectrometer, where a precise molecular weight is determined. Together, this gives a very clear picture of the sample chemistry, or at least their fragments. Through many decades of laboratory experience, scientists can deduce the original large carbon molecules. (I am excluding the tunable laser spectrometer instrument at this time, as that focuses on methane, water and carbon dioxide, and their isotopes... but hoping I don't get caught on this oversight!). Given that any positive results from SAM would be from carbon fragments, the official NASA excitement tamp-down could indicate that tracing fragments back to large organic molecules isn't clear and definitive. That, however, runs counter to the vast experience scientists have with these instruments.
SAM is also capable of detecting indigenous amino and carboxylic acids. While these are not generally grouped with hydrocarbons, scientists would call these organic compounds. Maybe a NASA media person missed that class about carbon-nitrogen and carbon-oxygen molecules... but at times like these, it seems that NASA has more PR people than scientists, and each word in the press release must have been vetted.
At this stage of the guessing game, with just a few days until the reveal, NASA gives us very little wiggle room. Was Dr. Grotzinger expressing an abundance of enthusiasm over nominal machine performance as opposed to revolutionary results? Is the NASA Media Affairs Office still smarting over ALH 84001? Can there be something exciting there, after NASA's repeated buzzkill? I cannot stop believing the answer is yes; there are revolutionary results coming from Gale Crater. My guess remains that the magnitude of the discovery will be directly related to the size of the carbon molecules... and the precise importance should be and will be argued about for months. The government hates nuance, and NASA has to play along.
Expending all this mental energy with the Martian Guessing Game may seem futile to many people, but it serves a real purpose. Over the last week I have tested numerous "what-ifs" against the sparse facts available. This is exactly what MSL mission scientists have been doing for years, with more brains and bigger budgets, but for the same end. To be mentally prepared, as the Boy Scouts suggest, is not a trivial exercise and it makes one a better explorer.
I hope to hear exciting news on Monday afternoon in Moscone Convention Center's largest conference room -- if not, then at the 2013 AGU meeting. If not then, maybe from President Clinton in the White House near the end of her 2nd term. She does have a knack for dealing with unfinished business.
Citations and Sources:
Pete Goldie holds a Ph.D. and 2 other graduate degrees from “old East Coast universities.” “I merely wish it known that I am a licensed ceramic tile & natural stone contractor and everything I write about space science is not only freely available but eagerly disseminated by federal government agencies through the judicious expenditure of income tax revenue.”