Thinking about new dimensions

In American Scientist, Sean Carroll reviews Lisa Randall’s Warped Passages and Michio Kaku’s Parallel Worlds.

A distinctive feature of Warped Passages is the discussion of two different ways of extending physics beyond the Standard Model: the bottom-up, model-building “Harvard” approach; and the top-down, string-theory “Princeton” approach. Both philosophies are interesting and important, and the study of extra dimensions has brought them into close collaboration. The perspective of someone who has been immersed in the details makes the discussion of this dichotomy an especially valuable feature of the book.

Michio Kaku’s Parallel Worlds: A Journey Through Creation, Higher Dimensions, and the Future of the Cosmos, although superficially similar to Randall’s book, actually differs significantly from it. Although Kaku worked on string theory in its early days, he has become well known more recently as a popularizer of physics, and this is evident from the text. Parallel Worlds is not written from the viewpoint of an insider relating developments as they occurred. It is telling, for example, that the bibliography consists solely of other books for a general audience, with no citations of the primary literature. Nonetheless, the presentation is extremely polished, and the discussion is invigorated by the inclusion of numerous interesting and revealing anecdotes about the participants.

Kaku is also very attuned to the fact that what interests the general reader is not always what interests the professional physicist. He is quite willing to discuss the possibility of life on other planets, or even the religious implications of the work he describes.