The Biggest Ideas in the Universe: Space, Time and Motion

"The nice thing Sean has done in this book is respect us as readers. He writes out an almost unintelligible equation, Einstein’s field equation, and says, ‘I’m going to tell you everything you need to know to understand it.’ It does feel, to me, like a completely intelligible, accessible course in gravity and general relativity. It is a bit like running up a hill. I run three-quarters of the way up and then have to stop and think, ‘Do I really understand it?’ I have gotten to points where I don’t completely follow everything, but I understand enough that I can keep going and get to the end. One of the other books on my list is Astrophysics for People in a Hurry, which is effectively the entire history of gravity as we understand it, all in one quick read. The Biggest Ideas in the Universe, by contrast, is gravity for people with plenty of time on their hands. It’s not a big book, but I had to stop sometimes, go back and read parts of it again. For me, it was not a linear progression. Climbing up the hill of knowledge came in fits and starts. But when I got to the end, I felt very accomplished. I have the same sort of relationship with gravity, after Sean explains it, as I have with cars. I know how to drive a car and generally how a car works, but that’s not enough to build a car. Sean is showing how gravity works, how Einstein’s equation works. I couldn’t use it to write a paper or do a PhD in physics. I could never duplicate it any more than I could build a decent car. But I can imagine the pieces turning inside an engine in much the same way that I can understand what Einstein’s equation does, thanks to Sean’s book. It’s part of Sean’s series of books. In this one, he’s taken on Einstein’s general relativity. It’s a very concise and—physicists would say—beautiful equation. In Einstein’s relativity, gravity, space, and time are all wrapped into this one equation. Sean breaks it down and tells you everything you need to know about the cutting edge of gravitational research, of general relativity research. In a nutshell, the book shows how professional physicists think of gravity today. It’s much more holistic than the gravity of a few years ago, or certainly before Einstein. It is really a deep dive into what gravity is from a mathematical perspective, but written in a way that you don’t have to be a physicist to understand it. He takes you through the mechanics step by step. He uses terms and examples that are familiar and approachable for most people. All together, Sean’s book is a detailed tour of the topic where, at the end, you really feel like you grasp what a physicist’s view of gravity is. It’s very different from some of the other perspectives that we’ll see in the other books we’re going to talk about."