In this installment of Jeff’s Notes, I will be summarizing and reacting to Lisa Randall’s recent book, “Dark Matter and the Dinosaurs.
“Dark Matter and the Dinosaurs” begins with a review of what astrophysicists know (or think they know) about the birth of the universe, the visible matter (like you, me, trains, and stars) in the universe, and the matter in the universe that we can’t see (but has to be there for reasons too technical to fully elaborate in Jeff’s Notes.) Scientists call this matter that we can’t see (because it doesn’t interact with light) “dark matter”. After introducing dark matter, Randall moves on to talk about seemingly unrelated events like, the extinction of the dinosaurs and the periodicity (regularity) with which comets may strike the earth. Then, Lisa concludes by uniting all three of this strange topics into one even stranger theoretical model. The model makes the prediction that some small amount of dark matter may interact weakly with other bits of dark matter. This would create a dark matter disk similar to the regular matter that we see in our galaxy. As our solar system moves through our galaxy, we experience different densities of light and dark matter. Randall argues that when our solar system passes near an area with lots of dark matter, the gravity from the dark matter is just enough to dislodge comets. That seems to explain the possible periodicity (regularity) of comets, and that periodicity of comet strikes just happens to coincide neatly with the comet strike that killed the dinosaurs. In short, this theoretical model suggests that dark matter may not be so neutral or inert as it may seem.
With her tortured metaphors, hopelessly out of date pop culture references (one can imagine the students in the back of her class rolling their eyes at her Facebook and Google+ reference in particular), and frequently awkward prose, Lisa Randall reveals herself as that adorkable science professor who made physics bearable for even the dimwitted liberal arts students like me. This book is a great primer on basic astrophysics. Her theory is fascinating, even if it’s almost certainly wrong, at least in part. Lisa has found a way to cross disciplines and weave a theoretical web through geology, astrophysics, and particle physics. Although, if you’re planning to read this book (and I would recommend it), I would recommend that you brush up on the Wikipedia entry for the Standard Model if you don’t basic particle physics (i.e. what the Higgs boson, quarks, and the strong nuclear force are ). Randall uses these terms like everyone is familiar with them.
Next up on Jeff’s Notes: “A Crack in Creation” by Jennifer A. Doudna and Samuel H. Sternberg