Feb 2013

Another example of why we’re looking for water.


Whether in our solar system or beyond, the search for habitable environments is tightly tied to a search for liquid water. The reason is that wherever we find liquid water on Earth, we find life. (The few caveats to this involve mixtures that are so salty that life can’t squeeze the water out of the environment.) So let’s take that as a hypothesis: where you find water, you find life. Absent a life-detection mission to another planet, or a telescope that can detect life elsewhere… how would you test that hypothesis? In other words, how can we test it on Earth?

One way to test it is to go to an environment that has tremendous hurdles for life to overcome, but plenty of liquid water. For example, here:

That’s a picture (of a picture) of a hole drilled through 9 football fields of ice. (I usually don’t go for the “football fields” unit of length measurement… but tis the season.) At the top of that hole is… well, this:

Yeah, that’s Antarctica. It’s COLD there. Oh, and don’t let all that snow fool you: it’s dry there. In fact, Antarctica is considered a desert because of the lack of rain or snowfall. (The reason there’s snow on the ground is that the small amount of snow that does fall never melts.) So you have to imagine yourself at one of the coldest, loneliest, driest places on Earth. Think Hoth. Got that? Now, drill down through half a mil– er, over 8 football fields of ice. So now its cold, dry, lonely… and dark.

Eventually, it won’t be dry anymore. Why? Because eventually you’ll get down to a layer of water — liquid water. But it’s still cold, dark… and lonely. There’s no sunlight for photosynthesis. There’s no warm place for life to live. There’s just… water and conceivably some nutrients.

This seems like a great place to test the “if there’s water, there’s life” hypothesis.

Can life live here? Well, the WISSARD team that drilled down there has just found life there. BUT HOLD ON A SECOND. Before you get too excited, they need to do more tests, to make sure they life they found lives in the lake, and wasn’t brought there by the expedition. The team has taken care to NOT contaminate the lake, but until they examine the organisms they cannot rule out contamination.

We’ll wait for confirmation of these results, but if they DID find life deep under the ice it would be huge for astrobiology. Not only would this affirm the “water —> life” hypothesis, it also would serve as an excellent analog for a future life-finding mission on an object with a sub-ice ocean (for example, Europa).

If you want to learn more about this, check out the WISSARD project’s home page. But you might have to be patient. At the moment I’m writing this, their server is down… probably because their awesome day is slamming their servers. Good problem to have. :-)

S. Domagal-Goldman Posted by
S. Domagal-Goldman
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  • http://www.facebook.com/ravi.k.kopparapu Ravi Kumar Kopparapu

    It’s possible to dig half a mile on Earth but can it be done on Europa where the depth of the surface ice is nearly 10 km ? We haven’t gone that far underground even on Earth.

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