If all goes well next month, Curiosity, NASA's latest mission to Mars, will land in the Gale crater, a 3.5-billion-year-old, 96-mile-wide depression near the planet's equator. Out will roll a car-size rover to search for signs of life, among other things. It will drill into rocks and sample the contents, using a mass spectrometer, a gas chromatograph and a laser spectrometer.
In the unlikely event that the project finds evidence of life, then what? In particular, who is in charge of deciding what we should do if we encounter living Martian creatures?
Please note that the chances of Curiosity finding actual microbes look very small. They probably lie deep beneath the surface, out of range of lethal radiation and beyond the reach of the rover's probes, and even then they will be rare, if they exist at all. A new paper, however, hints that there's a chance of finding organic molecules that may be characteristic of life. Alexander Pavlov of NASA and colleagues have calculated that simple organic molecules, such as formaldehyde, could survive as little as 2 inches below the surface of Mars, while in young craters more complex molecules like amino acids could be found at such depths.
But none of this would be actual life.
Even a promising fossil would leave doubts about whether anything still lives on the red planet. So the day when the discovery of Martian life is announced is still a very long way off. But perhaps it's time to start thinking about what should happen on that day.
In some ways it is bound to be an anticlimax. Like the announcement of the Higgs boson last week, however magical the moment may be in historical terms, it will not affect most people's daily lives. We can celebrate, congratulate, revel in the detail and philosophize on the meaning, but earthly life will continue as if little had happened.
Pretty soon, though, a political angle will emerge. For one thing, politicians and journalists from countries other than America will start to grumble that this discovery must "belong" to all humankind and not just to NASA. The U.S. government, despite having forked out all the costs of exploring Mars so far, including the $2.5 billion cost of Curiosity, will probably agree. But who will end up making the key decisions?
The United Nations is almost bound to set up an agency to oversee what experiments are planned, but the U.S. may prefer a different body. Private consortia may conceivably start to plan how to go and retrieve a sample, dreaming of the riches to be garnered from displaying it on Earth. If so, nongovernmental organizations will quickly begin to worry about the safety of such a scheme and to champion the rights of Martian microbes to be conserved and respected in their lairs.
“If NASA's Curiosity mission finds microbes, expect a power struggle on Earth to come next.”
In other words, the discovery of extraterrestrial life would produce some predictably messy earthly responses.
As far as I can discern there has been very little public discussion of these issues. The Outer Space Treaty, opened for signature in 1967 by the U.S., U.K. and Soviet Union and ratified by 100 governments, says that no country can claim political sovereignty over land in outer space. The treaty does not forbid private ownership of land in space, however, and it would be up to terrestrial courts to decide if such claims were recognized. Also NASA has clear policies on how to prevent the contamination of one planet with the life of another.
If we hear a radio signal from an extraterrestrial intelligence, there's also a protocol in place, drawn up by the International Academy of Astronautics and invoking three principles: that the decision on whether to reply should be made by an international body; that it should be sent on behalf of all humankind; and that its content should reflect a broad consensus.
But this is of no relevance to unintelligent Martian microbes. If extraterrestrial life is a mystery, so is the question of what we do when we find it.