You live on an alien world. Like, literally on it. Beneath your feet, caves, mines, and crevasses are filled with life that’s dramatically different from the stuff on the surface. So different, in fact, that NASA uses those lifeforms as a guide to its exploration of the universe.
Penny Boston is the new director of NASA’s Astrobiology Institute. Her job, when it begins on May 31, will be advising the agency in its search for life on other worlds. And believe it, there are plenty of candidates beyond Earth. Mars gets the hottest press, but Saturn’s moons Enceledus and Titan are both prime candidates, as is Jupiter’s Europa. Even cave life on the Moon is not out of the question.
Boston has a few more months to enjoy kicking around the caves in her current post as Director of Cave and Karst Science at New Mexico Tech. She took time out of her spelunking to chat with WIRED about her new gig, the globetrotting job of a cave scientist, and what life might look like on other worlds.
WIRED: OK, first I have to ask something I’m sure you get asked all the time: Your name is Penny Boston. Why aren’t you a detective?
Boston: [Laughs] Well I actually am in the other part of my life.
So do you really work in a cave all day?
When I’m not buried by paperwork, yes. I do a lot of work in subsurface and cave exploration and some work in mines, which are human-created caves. That gives us a window into Earth’s subsurface, where a whole lot of biology is going on.
Why is life in caves so interesting?
There’s a huge amount of it, for one thing. There’s an entire hidden part of planet that we don’t think about. The rock fracture habitat goes down to 5 kilometers, maybe down to 10, and is thoroughly infested with life forms. We think the great places for biodiversity are forests and corals, but so does the rock fracture habitat, and caves let us get in there. In the subsurface world, there are so many different ways of making a living. Surface life has photosynthesis, but subsurface only a tiny fraction of that energy trickles down. Not a lot of organisms are using organic material, they are processing minerals from rock they live in.
How can cave biology teach us about life on other worlds?
These organisms that live off minerals and not photosynthetically could be a model for another way life on Mars or Europa or who knows where else. As I went on evidence became clearer and clearer of caves on Mars, the Moon, and other satellites. It helps us really to stretch our imagination as we try to do life detection missions.
There is tremendous interest in icy moons with liquid interiors orbiting around gas giants. I think of them not as ocean worlds, but planet sized cave worlds.
What places in the solar system are you most excited about?
There’s a number of wonderful possibilities. Mars has garnered a huge amount of attention. There is tremendous interest in what people are calling ocean worlds, places like Europa and Enceladus, the icy moons with liquid interiors orbiting around gas giants. Personally, I think of them not as ocean worlds, but planet sized cave worlds.
And you mentioned that this life might not look anything like what we have on Earth. What do you look for?
Life is very good at making itself more orderly on the inside than outside. Life is like an entropy exporting machine, it keeps thermodynamics contained. Life takes energy from one form or another from the environment and uses it to make structure.
But the details of the chemistry may or may not resemble us. I think organisms probably have an inside and an outside, so they’re probably distinguishable from their surroundings. There may be life that lives on very different timescales, organisms that are very slow in their growth patterns. Thinking deeply about the fundamentals of what makes life life helps to inform us about how to go look for it.
What happens if somebody does find life out there?
Well, first I’m planning on throwing a big party. And then we have to consider very carefully how to study it without doing damage. This is an area where NASA is obligated by an international treaty on planetary protection. Early in the space age, our predecessors understood we didn’t want to contaminate other bodies with Earth life. And even though the chances are low of deleterious effects of alien life coming here, we still have to take extraordinary measures to make sure nothing bad comes back to Earth. I have served for a number of years on NASA’s Planetary Protection subcommittee.
If life is similar to Earth life, we need to figure out if it is similar because that is how the universe makes life, or because early lifeforms caught a ride from one planet to another.
Then, if we find another type of life, we have to ask if it is similar to us, or different. Has life arisen one time, or more than one time? We know, for example, that Mars and Earth exchange material. It’s a muddy situation. If life is similar to Earth life, we need to figure out if it is similar because that is how the universe makes life, or because early lifeforms caught a ride from one planet to another.
Your new job is in Silicon Valley. What are you going to do to scratch your itch to go caving?
Well, there are some wonderful caves elsewhere in California. Some fabulous marble caves in the Sierra Nevadas. My work has taken me all over world: sites in the Atacama in Chile, in Ukraine, Sardinia, wonderful caves in Mexico. And also here where I’m currently living in the American southwest. When I’m in the office in Silicon Valley my heart will not be far from many of those sites. In order to be an effective person I need to keep in touch with my roots in science and the natural world.
OK, cave biology is starting to sound kind of cool. Can you really sell it though?
I have to tell you that one of big attractions to me for working in cave environment was so few other people were doing it. It’s a vast, largely unexplored scientific treasure trove. All hidden. One of of my favorite sites is in Saudi Arabia. You’re in this big sand desert region they call the Empty Quarter. Yet there are caves there that contain snippets of life, these dive-able pools with all sorts of life that hasn’t seen the surface for years and years. The geochemistry, the mineralogy, is staggering. You can be in a wonderland with genuine scientific value, and it is a largely unexplored realm.
One of your other responsibilities at this new job is to educate and inspire the next generation of astrobiologists. How do you do that?
It’s not something you have to work very hard to sell young people on. Young people have a taste for exploration. Whether that’s physical and they want to go hike the Appalachian trail, or intellectual and they want to explore space.