Metaphysics: The Science of Life Book

An interesting overview of the science behind the theory that the dinosaurs went extinct because of a large asteroid/comet impact, and the ancillary theory that such impact are periodic.

Raup is a scientist who was working in the field at the time, and had papers published in journals. In particular, scientists such as Raup thought there was a periodicity to extinction events,and that this was perhaps evidence of some large object at the edge of the solar system that perturbed the Oort cloud. One possible such object is a brown dwarf star orbiting the solar system whose elliptical orbit brings it close enough to the Oort cloud, every 23m-30m years, to cause these perturbations. This star has been tentatively named Nemesis.

This book follows the arguments for and against firstly, the connection between a catastrophic impact and the extinction of the dinosaurs; secondly, attempts to periodize other extinction events; and thirdly, some of the possible causes of such periodicity.

Raup's initial work was done in 1984, and thirty years later the scientific arguments for and against periodicity and the possibility of a brown dwarf or large planet are still being thrashed out; see the Wikipedia page on Nemesis for an introduction to the continuing debate.

What I found most interesting about the book was its insight into the methodology of science; the vagaries of peer review, the punch and counter-punch of articles in journals, the gradual changes in consensus in a particular field as evidence and theories morph. If you are interested in "what science is" and how it works, I think this is an excellent read.