Astrobiology: A Multidisciplinary Approach
DOI: 10.1063/1.2435684
Astrobiology is the study of life’s origins and potential distribution throughout the Milky Way galaxy. Conceptually, the discipline has been around for hundreds, if not thousands, of years; however, it is only since the analysis of the Martian meteorite ALH84001 and the discovery of extrasolar planets in the mid-1990s that astrobiology has received serious attention from the broad scientific community. Sustained by NASA funding, notably through the creation of the NASA Astrobiology Institute (NAI) in 1998, astrobiology entered the mainstream of scientific discourse—although some recalcitrants still can’t resist referring to it as “bioastrology.” The funding profile for astrobiology has changed sharply over the past year, but popular interest in the subject has not: Astrobiology courses are now well established in the curricula of many universities, which shouldn’t be surprising because the subject is really about humankind and our place in the universe.
Astrobiology entered the fray as a disciplinary field only recently, thus the field is not overburdened with textbooks—good, bad, or mediocre. Most are introductory undergraduate textbooks in which the emphasis falls heavily on the “astro” and lightly on the “bio.” An Introduction to Astrobiology (Open U. Press and Cambridge U. Press, 2004), edited by Iain Gilmour and Mark Sephton, is probably the leading example of that type of textbook. Jonathan Lunine’s Astrobiology: A Multidisciplinary Approach is more balanced and much more ambitious in range and depth. The target audiences are graduate and upper-level undergraduate students, but the text is also an invaluable reference for researchers already working in the field.
Modern astrobiology demands familiarity with aspects of a wide range of disciplines, including astronomy, biology, chemistry, geology, physics, and planetary science. Lunine, a professor of planetary science and of physics at the University of Arizona in Tucson has been a key figure in the development of astrobiology as a discipline over the past decade. He is a researcher and, more important, a teacher. His textbook is the product of a well-tested lecture course and comes complete with questions that challenge and stretch students’ imaginations rather than invite regurgitations.
The textbook, although undeniably multidisciplinary, has the feel of having been written from a physicist’s perspective, albeit with more than a nod toward the biological sciences. After a brief historical overview, the following three chapters lay out the relevant basic physics (particles and forces), physical chemistry (quantum mechanics and bonds), and biochemistry (the cell and energy generation). The chapters are excellent introductions not only to the jargon but also to the science of the field, and they should be required reading for all aspiring astrobiologists who want to communicate successfully beyond their own specialist discipline. Of course, with only about 35 pages each, the chapters offer limited room for explanatory discussions; yet each concludes with a reference list and suggested supplementary reading material that can add depth.
The next 13 chapters provide a thorough discussion of the origins and diversity of life on Earth; the potential for life elsewhere in the solar system and among the nearer stars; the complications surrounding how we might detect and recognize that life if it’s there; and a brief final coda on the development of self-awareness and intelligence. Again, each chapter is bolstered by suggestions for supplementary reading material. Lunine does an excellent job of weaving together the variegated threads, demonstrating how the interactions across disciplines are essential in establishing the tapestry of life.
Inevitably, with such a broad reach, the text contains some omissions. Perhaps the most notable one is a thorough consideration of the terrestrial geological record. It would also have been useful for Lunine to include some discussions of galactography—the study of locations and characteristics of Milky Way objects such as solar neighborhood stars, star-forming regions (for example, Orion and Scorpius-Centaurus), spiral arms, and the inner Milky Way. Instead, the author presents those environments as abstractions. Astrobiology discussions, particularly with non-astronomers, sometimes lack a sense of place and scale. What’s where, and how did it get there? In the same vein, the discussion of extrasolar planets centers more on how to find them than on what we have learned from the planets we have found.
Yet in the final accounting, the above oversights are relatively minor, and one can imagine the screams from the publisher had the author tried to cram more material into a textbook already close to 600 pages long. Astrobiology is a welcome addition to the literature. It sets the bar at an exceedingly high level for future entries in the field.
More about the Authors
Iain Neill Reid. Space Telescope Science Institute, Baltimore, Maryland, US .
