We’ve sent several robotic space probes to Mars already, and several more will be heading to the Red Planet in the next few years. Mars is already the second most heavily explored planet in the Solar System, after Earth.
But our robots are forbidden by international law from entering regions where Martian water appears to be flowing, or regions where Martian life could hypothetically exist. Why? Because there’s a chance that microorganisms from Earth hitched a ride aboard our space probes, survived the journey to Mars, and might start to grow and reproduce if they’re exposed to Martian water.
Yesterday, we talked about a paper in the journal Astrobiology which argued that the risk of contamination is minimal, and we should let our Mars rovers do their jobs. Go explore, and if there’s Martian life, go find it! Today we’re looking at a response to that paper, also published in Astrobiology, in fact in the same issue of Astrobiology. A response which raises several concerns, such as:
- In the last few decades, we’re learned that Earthly microorganisms can be far more resilient than we ever imagined. Some of them very well might survive—and thrive—on Mars.
- We’ve also learned that Mars is far less hostile to life than we previously assumed. Quite a few microbes from Earth might find Mars a rather comfortable place to live.
Taken together, these two points suggest that we have not overestimated the risk of contaminating Mars. In fact, we may have drastically underestimated the risks, and we need to be more careful, not less careful, about where we let our Mars rovers go. Otherwise:
- We might destroy the very Martian life forms that we’re so desperately hoping to find.
- We might make Mars’s water undrinkable for future human settlers.
- We might end up misidentifying a stowaway microbe from Earth as a new form of life native to Mars, and the authors of this response paper argue that even our best gene sequencing technology might not be able to clear up the potential confusion.
Even if our Mars rovers keep their distance from Mars’s potentially-habitable or potentially-inhabited areas, there’s still a lot of valuable science they can do, especially when they’re investigating areas that used to be lakes or rivers, areas that could have supported lots and lots of alien life in the past, even if they’re bone dry and very thoroughly lifeless in the present.
So let’s take things slow. Let’s stick to the original plan (and current international agreements) and continue to explore Mars in a responsible and methodical manner.
Or maybe not. Gosh, I don’t know. After reading these two papers back to back, I really don’t know what to think.
Planet Pailly 
I can perfectly understand the arguments why we shouldn’t risk any kind of contamination. But, if humans do arrive on Mars, that will put an end to the debate. Is it possible that once humans arrive it might become impossible to determine whether life ever existed on Mars? If that is so, then it sounds like we have a window of opportunity to do these tests before the humans arrive.
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That was what the first paper was arguing. Humans will bring a whole lot more germs to Mars, which may make identifying actual Martian organisms even more complicated. But both sides raise some good points, so I really don’t know what we should do.
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Sensible is good by the sound of things!
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Maybe so. It’s scary to think we might destroy a thriving Martian ecosystem and then never even know we did it.
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That’s the thing… Manned trips to MArs would completely blow it.
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They probably would, which is the premise of the other paper. Go get this research done now before it’s too late.
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Yeah… The thing is of course we’re fairly sure there’s no little green men so what are we achieving by owning it?
Also… They have yet to find anything…
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Yeah, the whole thing seems very esoteric and hypothetical, worrying about alien life forms when we have no real evidence any such life exists in the first place. But it’s still something serious-minded scientists are worried about. I guess if there’s even a chance there might be life on Mars, we don’t want to mess it up.
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These debates and their uncertainties certainly add to the tension. I appreciate the need to move forward with care. We’re just beginning our space explorations. We live in exciting times!
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We do indeed! I’m constantly surprised by how much we don’t know about our own Solar System. We want to learn more as quickly as possible, but at the same time we don’t want to be reckless.
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Thanks for sharing!
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You’re welcome!
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It seems like detecting extraterrestrial life will unavoidably be a two step process. First, detect life. Second, determine whether that life is Earth life or something else. I suspect the second test will require far more sophisticated equipment than the first.
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That makes sense. I guess that’s what the whole gene sequencing argument is about. One side says gene sequencing will be able to distinguish between life from Earth and Mars, and the other side says that might not be enough.
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Fortunately this debate did not happen in the 1960s, or we never would have gotten to the Moon. Or sent probes out, for that matter. The Voyagers may eventually crash on a planet, in a distant galaxy, 15 billion years from now, and destroy a vibrant ecosystem via the introduction of our Terran elements.
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I think they were having this debate back in the 60’s. The Outer Space Treaty was signed in 1967, establishing the first international laws for space exploration. They just didn’t realize back then that our bacteria could do so well in space.
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