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

I love to watch Sean Carroll's videos and his method of teaching is unique and mesmerizing. However, his speaking skills don't translate well into the written media. In this way, I was a bit disappointed -- but maybe I was expecting too much.This is not to say that the book didn't fulfill its promises. It does.I thought the first third of the book was a good review of my long-ago 12th grade Physics class. But it soon began to blossom into more advanced concepts that were supported by a little more math than I had been hoping for. I thought he did an excellent job of leading up to and explaining the meaning of "curved spacetime", as well as how and why gravity modifies spacetime (the topic I was most interested in, for which I had to wait until Chaper 8).Admittedly, the math overwhelmed me in the later chapters, but it wasn't difficult to wreak out its meanings and results. I also appreciated the historical references to the pioneer physicists and their contributions to everything we know today.There are so many advances and discoveries that have been made in understanding our physical world in a relatively short period of time, as discussed in this book, but so many questions are still unanswered. Carroll leaves us with a kind of excitement in attempting to imagine what might be yet to come.

This book is a welcome relief from the many popular books on physics and other science topics which assume that books won’t sell unless they create analogies with phenomena which a third grader can relate to.In this book Carroll writes for intelligent, educated adults who had a good comprehension of calculus and geometry 30 or 40 years ago but eventually choose a career path that led elsewhere. Medicine in my case. So Carroll undertakes to begin at the beginning, giving a review of important math topics in a few pages. For anyone who has never taken a course in calculus or linear algebra in their lives, his book will be rough going. But for readers who only need a refresher, the book is a wonder. One thing I really enjoyed early on are the subtle connections Carroll makes in physics and math, where he points to a deeper, hidden understanding of certain topics. My college professors were too obsessed with proofs and exercises to point these out.The book moves at a brisk pace but Carroll isn’t writing a text book, he follows a rather quirky path which makes each page interesting, if not fascinating, pages worth pondering and enjoying.There is one improvement I would suggest, expressing more concepts in terms of units. For me anyway, thinking about the units involved in a concept often leads to quicker understanding. For example, early on when he’s discussing oscillators, he uses the common symbol ω, the angular velocity. But he never seems to mention that ω is radians/second. Anyone who hasn’t studied much physics would have difficulty here.

In reading the professional reviews of Carroll’s books I get the impression that he is the Carl Sagan of physics. His enthusiasm is palpable, his desire to bring physics into the mainstream is obviously sincere, and he makes a laudatory attempt to explain that physics is often, but not always, as advanced as the mass audience is often led to believe.Contrary to what the Wall Street Journal writes in its Amazon review, however, this book is not “reader-friendly,” assuming, of course, you do not have an advanced degree in physics or some variation of advanced calculus. For the rest of us, it is a very challenging read. And while that is not meant with any disrespect to the author, who is obviously brilliant and sincere, it is a warning to any potential reader looking for a comfortable winter read in front of the fire.I will, however, give Carroll great credit for not over-playing the hand of physics. He openly admits that physics, and by implication, science in general, is not the hard, granite-like “truth” that contemporary society often portrays it to be. “The science says” is often used today, with great exaggeration, in many news articles attempting to reinforce a conclusion that is far from conclusive in any final sense. Science is not like the ancient bone we dig up at an archeological dig. It is more like the conjecture we assign to that bone.Science, in fact, is not a body of knowledge at all. It is a methodology, or the outline of one, for discovering knowledge. But it is the equation, not its solution. And it is an equation that can take many different forms. There is not one equation, or very, very few, that rise to the level of “law.”Mathematics is no different. We didn’t “discover” it buried deep in the earth somewhere. We – humans – developed it. As the author notes, equations are “just a way to compactly summarize a relationship between different quantities.” And “A function is simply a map from one quantity to another quantity.” Mathematics, in other words, is simply a system or notation used to attempt to understand the world around us – emphasis on attempt.As a result, there are several models of reality, all mathematically “sound”, but often burdened by gaps and even contradictions between models. As Carroll notes, “We don’t know the final laws of physics, so we should be open to different possibilities while we think about what they might be.”And that, to me, is the money line of the book, which extends far beyond physics itself. “Science is empirical and fallibilistic – any of our scientific theories could be wrong, no matter how much evidence we have so far accumulated for them.” Which is why so many, and I do mean many, scientific theories are ultimately proven wrong and why things like clinical drug trials are often impossible to replicate.I attribute this to the infinitely broad umbrella of context. Nothing that we can observe or measure exists in total isolation. Context cannot, and in my mind never will be, reduced to notation, no matter how complex that notational language may be. Context is of infinite breadth and, perhaps more importantly, depth.Which is why I believe the title itself, with its use of the concept of “ideas”, is a bit inappropriate. Spacetime, to me, is not an idea. Beauty is an idea. Spacetime is a system for explaining one component of reality, but not, of and by itself, a piece of reality we found while hiking in the mountains. Ideas, to my way of thinking, are like shiny objects we discover in the rumpled fabric of reality.Having said all that, this is a very sound book for the right reader. If you are not already proficient in the notational language of calculus and physics, however, you will find it a difficult read. I will confess, however, there are moments of entertainment if you define entertainment as anything that brings anything positioned “beyond” us down to our very human level of understanding.Perhaps its greatest contribution, however, is that it does distill the greatest “laws” of physics posed to date into one modest-sized book. And it makes a valiant effort to tie them all together with a bow. That’s no small undertaking given that tomes have been written about most of them individually. For that the author is deserving of our thanks and our admiration and, if you’re up to it, our purchase.

This is the book that will teach you physics and about how the universe works and it’s very personal, he speaks to you like a friend and in this book there is no fluff, only information thank you Sean Carroll

My entire bachelors degree knowledge of physics is contained within the first half of the book (a bit disheartening…). I really enjoyed this read, however it packs a lot of subtlety that I’d probably have to spend more time to unpack. Unfortunately, I was never fluent in math as a language and although I can speak it conversationally the ultimate profound lessons require a fluent speaker. I would certainly recommend this book to anyone who has at least a high school level knowledge of physics and has been exposed to calculus.