Search for Life in the Universe ‐ What can we Learn from our own Biosphere?

Abstract

Space exploration has extended the boundaries of biological investigations beyond the Earth to other planets, moons, comets, meteorites, and space at large. This field is covered by the new multidiscipline of astrobiology which has focused on the different steps of evolutionary pathways through cosmic history that are related to the origin, evolution and distribution of life on Earth, or elsewhere in the universe. The over-riding objective of astrobiological research has been to attain a better understanding of the principles leading to the emergence of life from inanimate matter, its evolution, and its distribution, thereby building the foundations for the construction and testing of meaningful axioms to support a theory of life. In the endeavor to quest for life on other celestial bodies of our solar system or beyond, clues can be gained from the history of our own biosphere and its strategies to adapt to changing and even “extreme” environmental conditions. Assuming water in liquid phase as universal prerequisite for habitability, the neighbor planet Mars and Jupiter’s moon Europa are now favored targets of astrobiological research. 1 Astrobiology, a Multidisciplinary Approach Astrobiology is a relatively new research area that addresses questions that have intrigued humans for a long time: “How did life originate?”, “Are we alone in the Universe?”, and “What is the future of life on Earth and in the Universe ?” They are jointly tackled by scientists converging from widely different fields, reaching from astrophysics to molecular biology and from planetology to ecology, among others. Whereas classical biological research has concentrated on the only example of “life” so far known, i.e. life on Earth, astrobiology extends the boundaries of biological investigations beyond the Earth, to other planets, comets, meteorites, and space at large. Focal points are the different steps of the evolutionary pathways through cosmic history that may be related to the origin, evolution and distribution of life. In the interstellar medium, as well as in comets and meteorites, complex organics in huge reservoirs are detected that eventually may provide the chemical ingredients Reviews in Modern Astronomy 19. Edited by S. Roser Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ISBN: 3-527-40662-X