The Trouble with Physics by Lee Smolin

String theory has dominated physics for more than twenty years. There are actually thousands of string theories, but they all have limitations and none has provided the world with the Grand Unified Theory (GUT) that we all anxiously await.

This fact has been troubling a theoretical physicist named Lee Smolin and he has written a very thorough and readable book about it called The Trouble with Physics. (Houghton Mifflin, 2007.) His conclusion: "There needs to be an honest evaluation of the wisdom of sticking to a research program that has failed after decades to find grounding in either experimental results or precise mathematical formulation."

In 1968 a young Italian physicist named Gabriele Veneziano came up with a formula describing the probabilities for two particles to scatter from each other at different angles. By 1970 some physicists were able to express the data in terms of a physical picture in which particles could be seen not as points but as stringlike things existing only in a single dimension. They stretched when gaining energy; they contracted when giving it off; and they vibrated.

String theory in its various permutations became a hot topic in academic physics from around the mid-1980s, but by the end of the 1990s it had been suggested that all the conjectured and constructed string theories might be unified in a deeper (and mysterious) theory called M-theory.

According to Lee Smolin, the trouble with physics is not only that string theory may be wrong, but that its popularity has squelched innovative thinkers who wanted to take other directions within the field of physics. It became very hard for a physicist who was not interested in string theory to get a job. The academic and research communities simply did not provide jobs or grant money for physicists who disbelieved string theory or who wanted to pursue other avenues of research.

Wading through the actual physics in Smolin's book is a bit of a chore, but his critique of academia is clear and convincing. His overall tone is positive and upbeat in spite of the profuse apologies he keeps making to his colleagues in string theory. He ends with suggestions as to how to move the study of physics forward in ways that are more intellectually diverse than they have been in the era of string theory.