On Discovering Life

Sasselov-life_HS Dimitar Sasselov in Seed:

CERN’s Large Hadron Collider has begun refining our understanding of the fabric of space and time, and NASA’s Kepler mission is sharpening our estimates of how common Earth-like planets are in our galaxy. Yet as these cosmic-scale projects open the second decade of the new millennium they are returning science to a frontier that seems oddly 19th century. Science is going back to the scale of life—that middle ground of minute energies and high complexities that lies between the immense galaxies and the infinitesimal particles.

My statement that life is science’s new focus sounds naive and out-of-touch—after all, just open the newspapers or see the research budgets for biology and medicine, and you’ll notice an overwhelming amount of interest and funding for the life sciences. But that all has to do with us humans: first and foremost, with our health and bodies, and second, with our environment, the ecosystems of planet Earth. There is an aspect of life sciences that has been largely absent: the confrontation of fundamental questions of biology much as particle accelerators grapple with fundamental questions of physics. The roll call of early pioneers and prospectors is notable, but short. Fortunately, increasing numbers of researchers are now re-entering this fertile frontier.

The open secret of this emerging frontier is that we do not have a fundamental definition or understanding of life. Similarly, we do not understand life’s origins, how life emerges from chemistry. We do know that the chemistry of life on Earth, or “Terran” biochemistry for short, is rather restrictive in its molecular permutations. Unnecessarily so, it seems, given the enormous choice of good options provided by chemistry for building biological bodies and functions. However, we do not know whether nature or nurture is the reason. The bio-chemistry we see (and are!) could be universal, like gravity, where the same basic rules apply anywhere. Or our biochemistry could instead be one of many options, one that just happened to fit Earth’s environmental conditions.