Dimitar Sasselov is bent on expanding a public conversation between astronomy and biology. Between the infinitely vast and the infinitesimally tiny. Between “the big cold world of inanimate matter, plants, stars and galaxies — and what we call ‘life.’”
Where to look anew for extraterrestrial life is, relatively, the easy part. It’s on the earth-like planets (700-plus so far) that keep turning up on NASA’s space-based telescopes scanning the furthest stars. The hard part is just what to look for. “We don’t really know how to look for life that is anything but a carbon copy of ours,” Dimitar Sasselov is telling me.
We take it for granted that forces like gravity and the elements of our periodic table are everywhere the same, but what if life is not?
DS: Steven Jay Gould liked to say that if you rewind the reel and play the movie again — the movie, the history of life — it’s not going to be the same movie. And I believe he was right… It’s not going to be the same actors. It’s not going to be the same screenplay. But it’s going to be based on what’s near and dear to us. For life, that means there are functions which make a difference between life and non-life: the ability to self-sustain; the ability to adapt; the ability to create a system which is potentially and essentially eternal…
CL: What if the DNA and RNA decks — unlike the rules of gravity — have been re-shuffled out there?
DS: This is the big question. Not the historical origin of life, but: Is it a universal chemical law that biochemistries will be based on the same molecular rules as we are? Or are alternative biochemistries possible and, in fact, contingent on the environments that develop on those other planets? … Will we discover something we hadn’t imagined? Will we miss it altogether because we don’t know what we’re looking for?
The astronomist Dimitar Sasselov and I are picking up a conversation that began by accident late last year in the Boston Public Library. His work in the “Origins of Life” initiative at Harvard and his book on The Life of Super-Earths make a wonderful argument that science is social and that serendipity is vital. His main co-conspirator through through the last five years has been the Nobel Prize molecular biologist Jack W. Szostak, whose focus has been the lab construction of synthetic cellular life — light years, so to speak, from astronomy. Sasselov is remembering with pleasure, too, that he learned a lot about “the acoustics of stars” from horn players in the brass section of the Toronto Symphony Orchestra when he arrived from Bulgaria twenty-odd years ago. He pines a bit for the cross-pollinating “intelligentsia” of Sofia in the bad old days of his growing up. And he will make you wonder what it would take to generate a public conversation across the spectrum of basic and applied sciences that are humming inside the innovative core of Boston-Cambridge today. To me Dimitar Sasselov sounds like the sort of scientist the rest of us could rally round, and of course he makes me wonder how the curious minds of Open Source could get in on his project.
He had an adept answer on the general question of Earth chauvinism — on the patriotism of the planet that expects life everywhere to be an imitation of ours. Where, I asked, would he place himself between the intuitive notion of Earth and Us at the center of things and Douglas Adams’ retort in The Hitchhiker’s Guide to the Galaxy that we live on an “utterly insignificant little blue-green planet” with an ape-descended population so primitive we think digital watches are a big deal:
I think we are unique and exceptional, just because we explore this universe with our own roots. It’s a big point of my book that our planet is not the cradle of life or a home for life. The planet and life on it are the same thing. We are part of that living planet. If there are millions of those living planets in our galaxy, and there are a trillion of those galaxies out there, we are not alone… So yes, we are earth-centric because our roots are here, but that’s a good thing. That’s the same as bringing our own perspective to a brotherhood of perspectives out there — our own culture, if you will, where culture now is the biochemistry which makes us, where our self is not just homosapiens but the entire microbiome of trillions of microbes that live inside us, on top of us, as a part of ourselves. We are not who we think we are. And in a certain sense, that should bring us down to earth, literally, and also take this earth as one of those unique yet common trees of life which are, if not the first in this galaxy, certainly of the first generation in this young universe. So I see it both ways: I see both the Copernican principle of mediocrity: that we are not the center of this universe; and also I see us as proud Earthlings moving out there, exploring this universe and bringing with this exploration our own unique earthly roots with us.
Dimitar Sasselov, with Chris Lydon at the Harvard-Smithsonian Center for Astrophysics, February 21, 2012.