Sara Seager on Exoplanets

February 9, 2012

Sara Seager is one of the world's great planet hunters.  A planetary scientist and astrophysicist at M.I.T., she's one of the leaders of the hunt for new exoplanets -- planets the orbit stars other than our earth.  She's analyzing them for bio-signatures:  evidence of life.



Dear Prof. Seager,

I was appalled by your casual assumption of life elsewhere. 100 billion stars in a 100 billion galaxies may indeed be a large number. But that is no reason at all to assume that "life" will have occurred elsewhere. It is less than the number of molecules in a can of soup. You give the impression of having assumed this is true, therefore it must be true. Have you read Rare Earth? And they assume life emerges, at least at the level of bacteria. No basis for doing this. Like many physicists, you seem to think that life is far simpler than it is. Usually by are happy to contemplate "replicators" of some sort. But that isn't half of the problem. To form bods that won't break at RT, you need to be able to break the bond on one compound and transfer the energy to form an almost equally energetic bond between two totally different molecules. I agree, that somehow molecules shaking at 10*13/s for billions of years, "learned" this trick. But neither you nor I have any basis for assuming that this has happened elsewhere. I feel that your careless assumption that life is common is more likely to be seen as a grab for research funds. This not only brings science into disrepute, but it diverts resources from the real problem of humans getting through the next 50 years without crashing the atmosphere, the climate and civilization.
Please restrain your enthusiasm to those things about which you have some knowledge. Intriguing though it may be, the origin of life is not one of these things.

I look forward to your reply.

Prof. James Pawley

My belief in life elsewhere, indeed is a personal opinion, and should have been preceded by such a statement. If people on Earth do not understand the origin of life, that doesn't mean it cannot happen elsewhere.

The book "Rare Earth" is decidedly pessimistic. For a more balanced view, and one I agree with, see this review of the book. ""

Prof. Seager