Alien Investigator – Interview
When Ken Nealson thinks about extraterrestrial life, he pictures chemicals and energy flows, not clever ETs beaming radio signals. As the head of the Astrobiology Unit at NASA’s Jet Propulsion Laboratory in Pasadena, California, Nealson’s job is to figure out the fundamental properties of living things. He has spent years examining extreme environments on Earth–from lake-bed sludges to Antarctica to the driest deserts–for clues to how life might arise and persist in less-than-ideal settings. He recently gave a few tips to Discover associate editor Josie Glausiusz.
Do you think there are living things elsewhere in the universe?
I would be astounded if there weren’t. There’s so much energy out there. If you have energy flowing through a system, it seems almost an imperative that some form of life will evolve to harvest that energy.
What might extraterrestrial creatures look like?
It depends on the planet. On a very large planet with 10 times the gravity of Earth, it’s hard to imagine anything growing up in three dimensions, because the gravity would be so powerful. On smaller planets you can imagine big bulbous things.
Could there be life on Jupiter’s ice-covered moon, Europa?
Europa is interesting because it almost certainly has liquid water in it. Just how good a candidate it is depends on how thick the ice is. If the ice is kilometers thick and if there’s no easy way [for energy sources] to get through, then it’s going to be virtually impossible to make things like oxygen using photosynthesis.
What about life on Mars?
Nobody has shown me a single piece of data that makes me think there are living organisms on Mars, or that there ever were. But we will eventually look under the surface in places where, if there ever was life, it might still be hanging around or it might be better preserved.
If you could travel to any planet or moon, where would you go?
I’d like to go to Jupiter’s two moons farther out from Europa–Callisto and Ganymede. They both have ice and it looks like they still have volcanic activity. If I were the King of the Universe, I would be making a whole lot of orbiters to go get detailed information about a lot of the smaller moons and places where there might be niches for life.
Will humans ever colonize other planets?
I think it’s inevitable, unless we’re so stupid we kill ourselves first. In 20 years, we’ll probably have piloted missions to Mars. Beyond the solar system, that’s a heck of a question. We would need much more efficient and powerful systems for propulsion, but I think those will come. If someone had told my grandmother [in her youth] she’d be flying out here from Iowa in a plane, she would have told them they were nuts. And yet she did that.
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