HERE BE DRAGONS

Astronomer Koerner and biologist LeVay plot scenarios for extraterrestrial life in this sharp, enthusiastic, and skeptically tempered overview of “cosmic biology.” How to begin looking for life out there where the stars know no end? Koerner and LeVay begin on planet Earth, with a look into current speculations on the origin of life. What are the tolerable environments for the formation of organic compounds, whether they are catalyzed by RNA or polypeptides? If they can survive in the rudest environments on Earth, might they survive in the suspected briny seas on Europa, a Galilean moon of Jupiter? How could the compounds have been formed in and migrated through deep space, and how did they proceed from simple to complicated forms? Koerner and LeVay present theories that suggest answers to these questions, then tour the nurseries where stars are born to explain how the “unseen influences” that are extrasolar planets might contain life-nurturing habitats like our own. Physical and temporal characteristics of the universe also allow for speculation about the possibility of life beyond Earth. Sallying into a few of the imbroglios that currently ignite paleontology, astronomy, and cosmology, the authors decipher such feuds as the Stephen Jay Gould—Conway Morris debate over the conclusions to be wrested from the Burgess Shales, and ask whether Stuart Kauffman has a sense of just where complexity theory is going. Although chapters on UFOs and computer consciousness fail to inspire Koerner and LeVay to their usual high level of curiosity or energy, they hit upon a vexing final question: Might a “life” outside our ken even be recognizable by us? Not yet, anyway. Does the celestial vault support life other than our own? Koerner and LeVay, who came to the question with reservations, happily conclude by asking: Why not? “The trail of discovery hangs heavy with the scent of life.”