The Universe in a Nutshell

The Universe in a Nutshell (2001) is a book about theoretical physics written by famed physicist Stephen Hawking. It expands upon and updates many of the concepts contained in his earlier book, A Brief History of Time, and is usually considered both a sequel of sorts and a companion work to that very successful work; while it’s not necessary to have read A Brief History of Time to understand and enjoy the later book, it certainly helps. The Universe in a Nutshell reflects Hawking’s growing fame and the reputation of his earlier book in being of much higher production value, with many full-color illustrations and other elements.

In The Universe in a Nutshell, Hawking once again attempts to explain some of the most complex concepts and theories about how our universe came to be and how it works in plain, easily-understood language that minimizes math and emphasizes concepts. Hawking revisits many of the same topics as his earlier book, much of which hadn’t changed much in the intervening years. Written with humor and a firm understanding of how difficult these concepts can be for non-scientists, Hawking divides the book into seven chapters that are largely standalone, meaning they can be read in any order and do not depend on each other (with the exception of the first two chapters, which are closely related, and also serve as foundation for the concepts in later chapters).

Chapter 2 offers a simplified explanation of Einstein’s Special Theory of Relativity and his later General Theory of Relativity, published in 1905 and 1915 respectively. Hawking discusses how these seminal works revolutionized how physicists viewed the universe; the Special Theory demonstrating that matter and energy were simply different states, and proving via calculation that the speed of light is a constant that cannot be exceeded, while the General Theory gave us concepts such as the curvature of space-time due to gravitational forces. Hawking points out that almost all modern concepts of our universe stem from Einstein’s radical and explosive work.



Chapter 2 uses Einstein’s theories as a launching point for a discussion of time, offering up some of his own groundbreaking work as he explains how time can actually come to a stop when mass collapses to a density so absolute not even light can escape, and how this leads to the idea that the entire universe must have begun in a “big bang” of inconceivable pressure and energy.

Chapter 3 attempts to bring together Einstein’s theories and quantum mechanics, discussing the universe as a set of different “histories” described by these theories, and the work being done to combine them into a “unified” theory that explains, well, everything. As with all the subsequent chapters in the book, this chapter repeats many data points and concepts from the first two chapters, allowing it to be read on its own.

Chapter 4 gets into time, and specifically, whether it might be possible to look forward and glimpse or predict the future. Hawking complicates this fun sci-fi concept by contemplating how black holes—areas so dense they warp gravity and can even stop time completely—might destroy the information about the future we’re trying to look at.



Chapter 5 turns that concept around, wondering whether time travel could be possible. Surprisingly, he argues that a sufficiently advanced technological civilization should be able—in theory—to travel into the past. But he warns that this would rely on navigating probabilities that are so tiny and fleeting as to be almost certainly practically impossible.

In Chapter 6, Hawking theorizes on the future of the human race through a lens of constantly increasing complexity. He contemplates the ever-increasing speed of technological and biological advancement and posits that the future will be orders of magnitude different from our present in ways that our present isn’t from our past.

Finally, in Chapter 7, Hawking gets into the revised concepts of quantum mechanics, updating so-called “string theory” with “p-brane” theory, which includes the head-spinning possibility that our entire universe is actually just a hologram. This is by far the most complicated and difficult of the chapters, working to convey in words theories that are properly conveyed via math.



Throughout, Hawking uses a conversational tone to convey complicated subjects without resorting to the advanced mathematics that these theories are built on. Because each chapter is designed to be standalone in a sense, many basic concepts are repeated over and over again, but this has the benefit of giving the reader a chance to “catch up” with Hawking and commit these ideas to memory even if the reader isn’t particularly versed in modern physics. Although Hawking’s humor and casual tone are refreshing and make the book very enjoyable and entertaining, it also underscores a point Hawking makes several times: that his goal is to create a workable description of the universe, regardless of whether those descriptions have real meaning to people.