Earth-like Planets Aren’t Rare

10 Questions with...

Renowned planetary scientist James Kasting on the odds of finding another Earth-like planet and the power of science fiction.


James Kasting



Job title:

Distinguished Professor of Geosciences


Pennsylvania State University,
University Park, PA

The subject of this installment of Seed’s “10 Questions” is James Kasting, a geoscientist at Pennsylvania State University. Though ostensibly an “earth scientist” with an emphasis on atmospheric chemistry, Kasting’s expertise is quite literally out of this world: He’s responsible for much of the canonical research quantifying the physical conditions that allow planets to sustain life in the first place. This work allows scientists to better understand not only the origins of life on the ancient Earth but also the long-term fate of our world, as well as the potentials for extraterrestrial life both within and beyond our solar system. Kasting’s status as a leading expert in this increasingly active field led to his selection as chairman of NASA’s ongoing Exoplanet Exploration Program Analysis Group, and also informed his new book from Princeton University Press, How to Find a Habitable Planet.

[1] How do you explain your job at cocktail parties?

We are looking for evidence of life around other stars. This is a very old question. We now have the technology to actually do it, though!

[2] In the past six months, what has been the most exciting advance or breakthrough you’ve had in the lab?

Undoubtedly, the first results from NASA’s Kepler Mission, showing that this telescope can successfully find small planets around other stars by looking for transits. The really exciting data from Kepler should come within the next 2-3 years, as the project begins to be sensitive to Earth-size objects orbiting at Earth-like distances from their parent stars.

[3] Complete this sentence: We could make huge strides in the field, if we could just figure out…

How to convince NASA to fund the necessary space missions: the SIM Lite Astrometric Observatory and the Terrestrial Planet Finder. This would allow us to identify Earth-like planets around nearby stars and to eventually study their atmospheres spectroscopically, looking for evidence for life.

[4] What’s the biggest misconception about your field?

That the chances of finding another planet like Earth are poor. The book Rare Earth by Peter Ward and Don Brownlee has accentuated this perception. But they don’t actually argue that Earth itself is rare; rather they argue that complex life (specifically animal life) is rare. I don’t actually agree with that argument, either, but there is really no reason to think that Earth-like planets are rare.

[5] Scientist and non-scientist you’d most like to meet?

E.O. Wilson, and President Obama, respectively.

[6] What are you reading now?

I am reading a book on Sudoku and trying to get better at solving the puzzles.

[7] When I was a child, I wanted to be…

A scientist. And so it came to be. This should not be too surprising, as I grew up in Huntsville, Alabama, the home of Marshall Space Flight Center and the place where the Mercury, Gemini, and Apollo rockets were designed. I had the space program all around me.

[8] What advice would you give someone just starting out in your field?

Learn to write and speak, not just to crunch numbers. Whether you can get your message across is as important as the message itself.

[9] If the NSF surprised you with a $2 million grant tomorrow, what would you spend it on?

I would hire a full-time computer programmer and a couple of post-docs. And I’d probably update both my office PC and my laptop. I’m a theoretician, so I don’t really need that much money. On the other hand, the space missions we are talking about are very expensive—billions of dollars. For those, 2 million dollars wouldn’t even qualify as seed money.

[10] Why do you do science? What inspires you?

I read a lot of science fiction while I was growing up, authors like Isaac Asimov and Robert Heinlein. I bought into the notion that mankind has a future out there in space. And I watched a lot of Star Trek, which confirmed that belief.

Originally published March 15, 2010

Tags funding policy research space

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