Searching for an alien haven in the heavens.

Abstract

The first few articles in this issue of PNAS constitute the beginning of a two-part Special Feature dedicated to the study of astrobiology. Astrobiology is not an autonomous or self-sustaining discipline. Rather, it is a hybrid subject emerging at the crossroads of astronomy, geology, paleontology, physics, and biology. What at first pass may seem like an amalgamation of disparate fields, upon further review, is a clear and increasingly defined discipline. The roots of astrobiology are found in the 10 distinct goals set by the National Aeronautics and Space Administration (NASA) Astrobiology Institute. These objectives can be summarized into three branches: How does life begin and develop? Does life exist elsewhere in the universe? What is life's future on Earth and beyond? Some preliminary answers to these questions were addressed at the first large scientific conference dedicated entirely to astrobiology, held April 25–26, 2000 at the Ames Research Center at Moffett Field, CA. A few months later an international “Frontiers of Life” conference was held in France's Loire Valley. Sessions at those meetings ranged from “Water—the Sine Qua Non …