NASA last week promoted, as quietly as it could, laboratory work that suggests that organic matter may be able to survive for eons on the surface of Mars. “Missing Piece Inspires New Look at Mars Puzzle” read the headline of the press release that arrived in reporters’ inboxes early Friday afternoon, just before the long holiday weekend. Pretty mundane stuff, especially with the second sentence declaring that “this doesn’t say anything about the question of whether or not life has existed on Mars.”
But if NASA was playing down the new work to avoid another life-in-a-martian-meteorite media frenzy, it only partially succeeded. “Mars life may have been missed years ago” read the UPI headline, while BBC News went with: “Mars may not be lifeless, say scientists.” The problem was that although the NASA release may have had a cautionary note near the top, it had “Mars” and “life” in its first sentence. So the media’s treatment of the new paper—which was accepted 19 August for publication in the Journal of Geophysical Research-Planets—hewed closely to the life-on-Mars line. The front-page Washington Post story even had the long-discredited Face on Mars image, albeit on an inside page.
Not that reporters got their facts wrong. But they underemphasized caveats.
They duly reported that astrobiologist Rafael Navarro-González of the National Autonomous University of Mexico in Mexico City and his colleagues had replicated the unsuccessful search for organic matter—the “carbon-based chemical building blocks of life,” as the press release put it—conducted 34 years ago by the two Viking landers on Mars. Navarro-González and colleagues used Marslike soil from Chile’s Atacama Desert in Vikinglike analyses, but they only got negative, Vikinglike results if they added a bit of perchlorate salts first. Perchlorate was the Phoenix lander’s recent big find. Navarro-González concludes that there was perchlorate at the Viking lander sites, too, where on heating during the Viking analyses it would have oxidized and destroyed any organic matter.
So it would seem building blocks of life might well be on Mars but as yet undetected. Sounds like front-page news, but news stories ignored or played down another caveat in the NASA press release: Organic matter that has nothing to do with life is delivered to Mars by the ton every year in meteorites and cosmic dust. So even if the new lab experiments prove that there is organic matter on Mars, it says nothing about the question of whether life has existed on Mars, as the press release duly noted. Next up in the life-on-Mars saga is the Curiosity rover (formerly known as Mars Science Laboratory) to be launched in 2011. It will be able to detect organic matter without heating it in the presence of any perchlorates. But it won’t necessarily show whether the organics arrived via meteorite or were from life as we know it, on Mars