The Biggest Ideas in the Universe

from it for just a second, we expect the table to still be there when we turn back. If we place an apple on the table, we expect the table to support it, rather than the apple falling right through to the floor. As much as we might lament how difficult it is to predict the weather or future election outcomes, we should be impressed by how much reliable predictability there is.

Physics is made possible by this predictability. It may not be absolute, but we can somewhat anticipate what's going to come next in the world if we know what's going on right now. The most basic kind of predictability is conservation, the fact that some things don't change at all.

Conservation is just what physicists call "staying constant over time." You may have heard that energy is conserved, for example. Energy isn't a kind of substance, like water or dirt. It's a property that things have, depending on what they are and what kind of situation they're in. There is no "energy fluid" that flows from place to place. There are simply objects that have positions and velocities and other properties, and we can associate a certain amount of energy with them because of those facts.

An object can have energy because it is moving, because it's located at a high elevation, because it's hot, because it's massive, because it's electrically charged, or for other reasons. Under the right circumstances, those forms of energy can be converted back and forth between each other. The energy that a wineglass has just from being located on a table can, if the glass is knocked off the edge, rapidly be converted into energy of motion as it falls, and then into heat and noise and other forms of dissipated energy as it breaks on the ground. Conservation of energy is simply the idea that the total energy, given by adding up all the individual forms, remains constant throughout the whole process.

(Wait-is this circular reasoning? Are we merely inventing a

the whole universe. Carroll, who has long been one of my role models for exposition about the cosmos, dreams of a world where physics is hot gossip. With this book, he takes an important step toward making this idea a reality by giving people the tools they need so they too can understand the biggest ideas and questions in the universe. I can t wait to hear that people are arguing about beyond standard model physics at the Thanksgiving dinner table!
Chanda Prescod-Weinstein, author of The Disordered Cosmos: A Journey into Dark Matter, Spacetime, and Dreams Deferred

Sean Carroll's greatest gift isn't that he's an expert on the fundamentals of physics, which he is, but that he never speaks down to his reader. He assumes that anyone, even the uninitiated, can learn to understand the formulae that underlie complicated concepts like space and time. It is a pleasure to read his work, a greater pleasure still to get a world-class education from such a witty, thoughtful teacher.
Annalee Newitz, author of The Future of Another Timeline and Four Lost Cities

Do popular books about physics leave you feeling that you re just getting stories and not real science? If so, this is the book for you. In a clear and non-scary way, it explains the mathematical theories behind what physicists really think. Carroll s trilogy will plug a big gap in how physics is communicated to non-specialists and to judge from this first volume, will do so brilliantly.
Philip Ball, author of  Beyond Weird: Why Everything You Thought You Knew about Quantum Physics Is Different

Sean Carroll has achieved something I thought impossible: a bridge between popular science and the mathematical universe of working physicists. Magnificent!
Brian Clegg, author of Ten Days in Physics that Shook the World

Sean Carroll has produced a guide to relativity theory for the 21st century, plugging the gap between popularisations that emphasise the oddities without giving the facts, and textbooks that train students to manipulate equations without providing insight into what it all means. He will open your eyes to the way physicists view the universe, making fundamental ideas accessible without the need for a degree in science, but bravely ignoring the old adage that adding equations will scare readers off. Don t be scared; this is the best lay-person s guide to the subject, written in an accessible, entertaining style and impeccably accurate. And the author promises to tackle quantum theory next! I can t wait.
John Gribbin, senior honorary research fellow in astronomy, University of Sussex

Carroll takes readers on a remarkable journey through some of the most important ideas in the field and lays out how those ideas become manifest in mathematical form. It s a bold move, and through it Carroll is able to take his readers on a much deeper exploration of foundational notions like force, motion, and momentum than other books manage.... If you are interested in physics, you should read this book. It can open a window through which your view of the Universe will be richer, subtler, and way more awesome.
Big Think

If you are trying to find a short treatment of the key ideas of physics that is genuinely accessible to pretty much anyone with a high school math background... Sean s two big strengths are an easy, informal manner of exposition and a gift for focusing on the physics and not letting the reader get lost in the weeds. The Biggest Ideas in the Universe exemplifies Einstein s quote that everything should be made as simple as possible, but no simpler.
3 Quarks Daily

I simply love it... Carroll is aware that you need to understand the math to truly comprehend the physics that underpins our greatest brainchildren. He diligently explains the concept of infinitesimal changes, for example, so that readers understand why Isaac Newton had to (co)invent calculus to explain planetary orbits. Over the course of the book, readers go from learning how to take a derivative to gaining an appreciation of the metric tensor that describes spacetime.
Seyda Ipek, Carleton University, Physics Today

Anyone who is interested in fundamental physics is encouraged to read this book, especially young people interested in studying physics because they will get an excellent idea of the type of physical arguments they will encounter at university. Those who think their mathematical background isn t sufficient will likely learn many new things, even though the later chapters are quite technical. And if you are at the other end of the spectrum, such as a working physicist, you will find the philosophical discussions of familiar concepts and the illuminating arguments included to elicit physical intuition most useful.
Martin Bauer, University of Durham, CERN

No-nonsense, not-dumbed-down explanations of basic laws of the universe that reward close attention.
Kirkus

One-of-a-kind Carroll flips the script and illuminates the form and beauty underlying a discipline that helps us understand all that exists.
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