The Cosmic Community
Among a tiny community on the third planet of an unremarkable star in a typical galaxy in a universe some twelve billion years old, a new science has taken hold. What does this upstart field of astrobiology aspire to? What is its mission? Something quite extraordinary and profound: to grasp the history of life in a way that has not before been possible. Until now, we have had access to a single biological narrative—the complex yet parochial tale in which we ourselves are characters. How much of a part did chance play in the process that gave rise to us? To what extent could our story have been different? Terrestrial biology cannot answer these questions. But by revealing alternative sagas of life on other worlds, astrobiology will show which aspects of evolution are inevitable and which are capricious—contingent—wherever organisms appear.
Astrobiology will also let us see ourselves in a truer context. We've been alone to this point: the totality of known life confined to a single ball of rock in the vastness of space, and a common genetic heritage. Astrobiology will end that isolation. It will widen our sense of community to embrace the universe as a whole and all of its inhabitants. We'll begin to regard Earth not just as an ordinary planet but as an ordinary living world among many, and terrestrial life as but one species of a far more inclusive biota.
Ultimately, astrobiology aims for a unification as grand as any in particle physics: the unification of biology with cosmology. Its goal is nothing less than to understand, in a way that is both detailed and synthetic, how life springs forth from the evolution of the universe.
In the broadest sense, life everywhere enjoys a mutual kinship, a shared genealogy rooted throughout the cosmos in a common set of physical laws and raw materials. That much is already clear. But, additionally, astrobiologists have rallied around a number of ideas and principles that, based on our