Last week, according to the Washington Post and many other reports, NASA scientists detected water vapor on Mars. Almost simultaneously, NASA personnel exploring the Cordillera de la Sal (pictured here), near the Chilean town of San Pedro de Atacama, also announced the discovery of water while exploring a cave in one of the world's driest deserts. The latter expedition is in fact intended to have Martian applications - if water can support life here, so goes the thinking, it might also do so in Martian caverns.
According to expedition scientist J. Judson Wynne, the Atacama water was utterly unexpected: " Why was water there? Is this merely a phenomenon related to these caves in particular? Is there some sort of moisture sink that results in the water concentrating in certain caves and not others in the Atacama Desert?" I'm surprised, though, that Wynne was so surprised - in such a vast, thinly populated place as the Atacama, where settlements have always concentrated at oases, the water table is uneven, and distribution of the Pleistocene fossil water is irregular. There are likely other similar sites, but with access too poor to support human settlement. The Atacama still holds many more secrets than any single expedition is likely to discover.