The Universe in a Nutshell (2001) was Hawking's follow-up, written for readers who found the first book hard. It is shorter, full of color pictures, and each chapter can be read on its own after the first two. The title comes from a line in Shakespeare's Hamlet: "I could be bounded in a nutshell, and count myself a king of infinite space."
Key idea
The book covers relativity, the shape of time, how the universe began, whether we can predict the future, whether time travel is possible, and newer ideas such as branes. Hawking says plainly which ideas are well tested and which are guesses.
Borrow the book
The Universe in a Nutshell by Stephen Hawking is still under copyright, so we do not reproduce it. Find it at a library: Open Library or WorldCat.
Reading guide, chapter by chapter
| Chapter | What it is about, in our words |
|---|---|
| 1. A Brief History of Relativity | How Einstein came to special and general relativity, and why light's speed being the same for everyone changes how time and space behave. Tested or speculative: Well tested |
| 2. The Shape of Time | Time as a dimension that can be bent, and "imaginary time," a mathematical tool Hawking used to describe the beginning of the universe. Tested or speculative: Relativity: tested. Imaginary time: a mathematical idea |
| 3. The Universe in a Nutshell | How the whole universe might have grown from something tiny, with inflation and quantum effects. Tested or speculative: Partly tested (the big bang); partly speculative |
| 4. Predicting the Future | Why the future is hard to predict exactly: chaos, quantum uncertainty, and what black holes do to information. Tested or speculative: Mixed |
| 5. Protecting the Past | Whether the laws of physics allow travel to the past, and Hawking's "chronology protection" idea that they may prevent it. Tested or speculative: Speculative |
| 6. Our Future? Star Trek or Not? | How fast knowledge, technology and people themselves might change in coming centuries. Tested or speculative: Hawking's own forecasts |
| 7. Brane New World | The idea that our universe might be a surface (a brane) in a space with more dimensions. Tested or speculative: Speculative; not tested |
How to read a science book like this
- Keep a note of three kinds of claims: things measured and tested, things predicted but not yet tested, and the author's guesses.
- Look at the pictures before the text; this book was designed around them.
- Read chapters 1 and 2 first, then any order.
- When you meet a big number, write it in powers of ten and compare it to something you know.
Worked example: Time slows down
In relativity, a clock moving at 87% of light speed ticks at half the rate of one at rest. If 10 years pass on Earth, how much time passes for a traveler at that speed?
- Half the rate: $10 \times \dfrac{1}{2} = 5$.
Answer: 5 years. This slowing has been measured with fast particles and with atomic clocks flown on airplanes.
Common mistake
Treating every idea in the book as proven. Hawking himself labels some as speculation. Relativity is tested; branes and time travel are not.
Read more: The Universe in a Nutshell.