On first glance, this book raised my scientific hackles. ‘Why we have already found extraterrestrial life? What kind of nonsense is this?’ I thought to myself. That attitude remained until I had finished reading the introduction.
Misleading title aside (you won’t be astonished to hear that we have not already found extraterrestrial life), Schulze-Makuch and Darling have written a solid astrobiology popular science book. While the authors have a tendency to extrapolate tentative evidence somewhat beyond the realms of rigorous science, and take an extremely optimistic viewpoint when reviewing each piece in the puzzle, that does not detract from the scientific reasoning made in each case. Every sign of alien life they identify may indeed turn out to be an actual one, however remote that probability actually is.
The first section of the book is devoted to investigations of the planet Mars, with the controversial results from the Labelled Release experiment on the NASA Viking probe, and the martian meteorite ALH84001 being brought under particular scrutiny. From there the search heads off to the moons of Europa and Titan, and thence thence to exoplanets, even pausing to investigate the habitability of Venusian clouds. All the way along this journey, indicators and markers of biological activity are presented in turn, and potential habitats identified in a consistently insightful manner. It really is a shame that all this comes close to being undone by the constant need to draw dramatic conclusions on scant evidence. It may have been better to have instead subtitled the book something like ‘Potential Habitats for Life in the Universe’, and included a little less hyperbole. This is a well-written, well-referenced book on the search for life in the universe, but one that needs to be taken with a large grain of salt.
Reviewed by: Euan Monaghan, The Open University