Exobiology revisited

The term “Exobiology” was introduced about 25 years ago, at a time when intensive discussions were under way concerning plans for the biological exploration of Mars. The search for life on Mars was to be a critical test of the concept of chemical evolution- not an end in itself. After the Viking mission, when it became apparent that prospects were dim for the discovery of extraterrestrial life within our solar system, many people concluded that this new field of endeavor would soon expire. Quite the contrary, over the past decade, the field has broadened considerably into a multidisciplinary approach to understanding the circumstances that led to the origin of life and the interplay between the evolution of this planet and its biota.