Cosmic Biology

In Cosmic Biology, Louis Irwin and Dirk Schulze-Makuch guide readers through the range of planetary habitats found in our Solar System and those likely to be found throughout the universe. Based on our current knowledge of chemistry, energy, and evolutionary tendencies, the authors envision a variety of possible life forms. These range from the familiar species found on Earth to increasingly exotic examples possible under the different conditions of other planets and their satellites.
Discussions of the great variety of life forms that could evolve in these diverse environments have become particularly relevant in recent years with the discovery of around 300 exoplanets in orbit around other stars and the possibilities for the existence of life in these planetary systems. The book also posits a taxonomic classification of the various forms of life that might be found, including speculation on the relative abundance of different forms and the generic fate of living systems. The fate and future of life on Earth will also be considered. The closing passages address the Fermi Paradox, and conclude with philosophical reflections on the possible place of Homo sapiens in the potentially vast stream of life across the galaxies. It is very unlikely that little green humanoids are living on Mars. But what are the possible life forms that might exist in our Solar System and how might they have evolved?
This uniquely authoritative and imaginative book on the possibilties for alien life addresses the intrinsic interest that we have about life on other worlds - reinforcing some of our assumptions and reshaping others. It introduces new possibilties that will enlarge our understanding of the issue overall, in particular the enormous range of environments and planetary conditions within which life might evolve.
Cosmic Biology
-discusses a broad range of possible environments where alien life might have evolved;
-explains why carbon-based, water-borne life is more likely that its alternatives, but is not the only possiblity;
-applies the principles of planetary science and modern biology to evolutionary scenarios on other worlds;
-looks at the future fates of living systems, including those on Earth. Life may unfold in various forms throughout the universe, constrained by universal physical laws and consistent principles of organic evolution, but propelled to great variety in detail by local conditions and the specifics of planetary history. What is known of the chemical and physical conditions of any planetary environment and its history enables us to make educated and plausible speculations about the nature and history of life on that world.
Within our Solar System, there is an enormous diversity of planetary environments. On Earth, life evolved on a geologically complex, water-rich world, which today has an oxidizing atmosphere, although this was not always the case. On Mars, the surface is bitterly cold and dry, and the atmosphere very thin. Whether or not life ever existed on the Red Planet is a matter for speculation, but we do know that early in its history, Mars was a warmer, wetter world. Today Venus is a planet with an incredibly hot surface and a dense choking atmosphere, and it seems unlikely, although not impossible, that life could ever evolve here. On the gas giant planets, such as Jupiter and Saturn, it is possible that life might exist in the dense atmospheres of these cloud covered worlds, and might even have evolved on some of their exotic moons such as the sulphur-rich, volcanic world Io, Icy Europa with its possible sub-surface ocean, or Titan with its lakes of liquid petroleum gas on the surface.
Discussions of the great variety of life forms that could evolve in these diverse environments have become particularly relevant in recent years with the discovery of around 300 exoplanets in orbit around other stars and the possibilities for the existence of life in these planetary systems.