Curiosity on Mars
NASA’s $2.5 billion mission paid off as Curiosity lands on Mars. Never mind that Google placed the news second behind the latest nut shooting. This is how space was supposed to be–risk all to gain all. The ultimate Olympic team.
What will Curiosity find there? As it happens, during my “vacation” I was reading about microbial colonization in dryland systems. Frank Herbert, we may recall, dedicated Dune to “the dry-land ecologists.” Dryland, arid, or desert is defined not (as you might think) as a place where no rain falls, or where there’s no humidity, but as a place where water evaporates faster than rain falls. The most extreme dryland on Earth, the Atacama desert in Chile, indeed has nearly no rainfall; but the air contains enough water to precipitate fog and dew. The fog off the ocean supports “lithic biofilms” –microbial communities living on or within the rock itself. Microbes called haloarchaea can grow even in the interstices of halite crystals, the most water-sucking habitat known. Now we even find cyanobacteria growing there, conducting photosynthesis while protected from UV.
In fact, the authors note, no matter how dry the landscape on Earth, even the coldest, microbial life finds “oases” within rock. “Thus, it seems that there is no aridity-defined limit to terrestrial life on Earth.” Is there on Mars? Let’s hope Curiosity turns over enough rocks to find out.