Q&A with Astrobiologist and Planetary Scientist, David Grinspoon

Issue Date: 
March 28, 2016

If space really is the final frontier, David Grinspoon is among its most dedicated explorers. Grinspoon is an astrobiologist, and he studies the origin, evolution, and distribution of life in the universe. He will speak at 4 p.m. March 31 at the University of Pittsburgh’s Department of Geology and Environmental Science Colloquium, 154 Chevron Science Center. 

A senior scientist at the Planetary Science Institute, based in Tucson, Ariz., Grinspoon is on the science team for the spacecraft that is currently exploring Mars and Venus. In 2013, he served as inaugural Baruch S. Blumberg/NASA Chair in Astrobiology at the John W. Kluge Center of the United States Library of Congress, researching and writing a forthcoming book about human influence on Earth, seen in cosmic perspective. His book, Lonely Planets: The Natural Philosophy of Alien Life, won the PEN Center USA Literary Award for Research Nonfiction. 

David Grinspoon

Astrobiology is the study of life on Earth and in space, including the search for habitable environments and even alien life forms. How did you become an astrobiologist?

I went to grad school in planetary science because there was no such thing as astrobiology. There was exobiology, but studying alien life was on the fringe, not entirely reputable. Then, in the ’90s when I was just starting my career as an independent scientist, there were several discoveries that made it much more promising that we could actually discover extraterrestrial life. NASA funded the Astrobiology Institute in 1998, and astrobiology was born. I guess my timing was good! 

Is it really possible that there is alien life beyond Earth?

First of all, it is possible that no one is out there. In a way, discovering that would be an even more fantastic thing than finding life. That would mean that there’s something so special, extraordinary, and strange about Earth. But we don’t have any indication of that, and everything we’ve discovered points toward there being other environments similar to the environment that allowed life to form on Earth.

What attracted you to the exploration of outer space?

Like a lot of space scientists of my generation, I’m a child of Apollo. I was in 4th grade when Neil (Armstrong) and Buzz (Aldrin) landed on the moon and hopped around on television. That was just so captivating. And I was a science fiction geek and got caught up in the excitement of space exploration and the idea of this future that we were inventing. When I went to college, I had summer jobs doing research on NASA projects with some of the early planetary missions. I worked one summer with the Viking lander, our first Mars lander, and I had very inspiring mentors. One thing led to another.

What are the greatest obstacles to finding extraterrestrial life?

The barriers to finding extraterrestrial life are very real. The exoplanets are so ridiculously far away that a spacecraft could not reach them in any of our lifetimes. So we are stuck with remote sensing of objects that are very, very far away. But we do know how to build instruments that should be able to focus on nearby planets—on stars that are only a few tens of light years away. We should be able to build instruments that can tell us a lot about the physical qualities of those planets, most importantly their atmospheres. If you look at Earth, the only inhabited planet we know, you can see that the atmosphere is radically changed by life. If you looked at our planet from one of those stars with the same kind of instrument we’re talking about building, you’d say, “Wow! There’s something happening on that planet!” So, ideally, we could find a similar, obvious signal on one of these nearby planets if we build the right instruments.

So, if I’m to buy real estate out there in the universe, where’s my best bet?

There are a few places in our own solar system that possibly qualify but we haven’t searched yet. Jupiter’s moon, called Europa, is an interesting one because we know it has an underground ocean of liquid water. We’re working on designing a spacecraft to go there hopefully in about a decade to look more carefully. There are a couple of other places in our solar system that we haven’t ruled out. Deep underground on Mars is a possibility because there are probably pockets of liquid water.  There are even more exotic places like the clouds of Venus that we can’t rule out because we haven’t explored them very carefully. There is liquid water in those clouds. 

The big news in the past decade or so is the disc of planets around other stars. We simply don’t have the tools yet to examine them in ways that could help us determine if they’re inhabitable. There are some next-generation space telescopes on the drawing board that would enable us to probe the atmosphere of some of these exoplanets and see if there’s anything that seems to be breathing the air and exhaling telltale gasses. We may be able to do that and learn something fantastic, but we don’t have the tools yet.

What do you want to achieve before you finish your career? 

It’s difficult to boil it down into one thing. The thing I do in my research is to model the evolution of the planetary climate. I’m trying to understand and help to devise general principles for how planets evolve and for how habitable conditions arise on planets and how they can be destroyed. I guess I would like to have contributed to a greater understanding of how planetary climate evolved and how that limits and enables life to exist on certain planets.