Life on Mars? Good News May be Bad News

There's growing evidence that the current explorers of Mars (especially Opportunity) are observing liquid water on the surface. It's an essential, key ingredient in life as we know it. And a look back at the inconclusive results from the Viking landers back in 1976 suggests that maybe they found signs of life after all.

Which may not be the good news that space-exploration enthusiasts think it is. Sure, it would get a lot of people very excited about space, and Mars in particular. But it could be a serious stumbling block to further exploration, and definitely to exploitation.

Remember in The Wrath of Khan when Commander Chekov was scanning Ceti Alpha 5 for life before testing the Genesis device there, and his captain said that even a microbe meant the test would be off? The Prime Directive forbids interference with evolving life. Remember what happened to the invading Martians at Grover's Mill NJ? They're highly vulnerable to Terran bacteria, after all.

But seriously... a dead, sterile Mars is one we could start sending people to, and eventually set up a permanent settlement (with waste products and all). But one with actual life would - for scientific, and arguably for moral reasons - have to be quarantined.

The dozen or so landers that humans have sent to Mars over the past few decades (only a handful have been successful in sending back any data) have all had very little risk of contaminating Mars with terrestrial life. They were sterilised before launch and few organisms would have a chance of surviving the trip, what with the cosmic radiation, the vacuum of space, the heat-blasting of atmospheric entry, and the alien atmosphere. But you can't sterilise human explorers - we'd go to great lengths to prevent that, actually - and unless you adopt a pack-it-in-pack-it-out policy for waste products - including the air they exhale - you're inevitably going to introduce alien lifeforms into the Martian biosphere.

From that point on, any attempt to study Martian life would be tainted by the "but we might have brought these with us" disclaimer. And while it's more likely that our microscopic cousins would find Mars excessively hostile and - like the invading Martians in War of the Worlds - succumb to any local microbes, there's also precedent for introduced micro-organisms devastating a local population with no defences against them (e.g. Native Americans when the Europeans invaded).

The Moon is closer, and Venus is nearly the same size as Earth, but Mars is definitely the most Earth-like place we've seen. I'd love to see humans exploring it and setting up research stations like in Antarctica. But I'd give that up forever in exchange for the knowledge that there is life out there... and that it didn't come from here.