Dark Matter and the Dinosaurs

This book is a lot. It starts with cosmology and the Big Bang, goes into particle physics to explain what dark matter is, touches on theories of the origin of life, finally gets to the fossil record and what that tells us about mass extinction events, goes into some concepts of probability theory and statistical significance, then describes large scale features of the Milky Way and our solar system's traversal through it.

All of this is used to illustrate her idea (which she is very careful to describe as speculative and a “thought experiment”) that there is a disc of dark matter, much thinner than the distribution of normal matter, through the central plane of the galaxy, and that the spike in gravity caused by this disc is responsible for knocking objects out of the orbit of the Oort cloud at the edge of the solar system every 30-35 million years and sending big spikes in the number colliding with Earth, causing mass extinction events including the death of the dinosaurs.


Randall is very clear, though out the work, that some ideas are not established yet and should not be taken as factual, but she does heavily reference other academic work on the variety of fields involved. As a nonexpert I am unable to verify all of the background material, but provided there are no glaring omissions or misrepresentations I believe she makes a compelling case for her theory.

Overall this book is densely packed with a lot of science and will take some thought to follow, but the frame of her “dark matter killed the dinosaurs” hypothesis allows the book to flow reasonably well.