The world around us is made up of atoms, and atoms are made up of subatomic particles, such as protons, neutrons, and electrons. But what are those subatomic particles made up of? The leading idea is known as string theory, which suggests that they’re made up of tiny little strings. If you could zoom in on a particle with an ultrapowerful microscope, you wouldn’t see a billiard ball or a point—you’d see an itsy-bitsy rubber band or a miniature guitar string.

If the string vibrates one way, as if playing an E-note, it might be an electron, and if it vibrates another way, as if playing a C-note, it might be a piece of a proton. So string theory unites all the different building blocks of nature into a single type: the string.

Strings may be small, but their implications are huge. They don’t just unite subatomic particles, but even things we don’t normally think of as things, such as forces, space, and time. String theory melds the theories that underpin all of modern science and technology: quantum theory and Einstein’s theories of relativity. If string theory is right, it goes right to the foundations of physical reality. Through it, human beings will finally know the principles that ultimately govern the universe and make it a place fit for us to live in. Many of the aspects of the world that seem so strange to us now will fall into place.

Scientific revolutions, like the political sort, are messy. The effort to produce a unified theory of physics is no exception. String theory has come in for some very public criticism, some of which is justified, some of which is unfair. String theory may well be wrong. It has yet to be developed fully, let alone tested in any convincing way. What this book lays out for you is cutting-edge science. It’s not always neat and tidy, but that’s what makes it fun.

In this book I cut through the jargon and the controversy to provide an up-to-date account of what string theory says, what it means not just for physics but for the wider world, and how it’s starting to be tested at new scientific instruments such as the Large Hadron Collider, the giant particle smasher in Europe due to fire up this summer. I survey not only string theory but also the other leading contenders for a deep theory of nature such as loop quantum gravity and “buckyspace,” drawing out the similarities and differences among the theories and how they bear on the mysteries of nature such as black holes, extra dimensions of space, and the possibility of time travel. If you’ve ever wondered how quantum particles are like David Beckham, this is the book for you.

For a more extensive discussion, read my interview for the Mental Floss blog. Book excerpts are available at, Google Books, and eBooks. You can see other reviews at GoodReads, LibraryThing, WeRead, eBooks, and The book was mentioned in the September 21, 2009, issue of Forbes.


About the Book

String worldsheet

Four-dimensional cube