Parallel Worlds

Cutting-edge physics for a popular audience. This time out, Kaku (Physics, CUNY; Hyperspace, 1994, etc.) takes us through the broad outlines of what physicists call Theories of Everything. The hottest new flavor here is M-Theory, a derivative of string theory in which our universe is considered to be one of innumerable parallel universes separated by tiny distances in eleven-dimensional space. While apparently counterintuitive, such theories arise from the solid twin pillars of modern physics: quantum theory and general relativity. Kaku dutifully steers the reader through the key formulations of physics, with brief glimpses of the scientists behind the big ideas: not only Newton, Einstein and Hawking, but the playful George Gamow, who did as much as anyone to make the Big Bang respectable, and the wisecracking Richard Feynman, who cheerfully admitted that nobody really understands quantum theory. We also get a look at the hardware of today's science, from the atom-smashers that generate new particles to the giant telescopes that peer back toward the origins of the universe. Kaku clearly enjoys speculating about the broader implications of his subject, and he cites several SF novels with obvious familiarity. His concluding chapters offer a discussion of some ways an advanced civilization might escape the heat death of the universe by tunneling into a parallel universe where the stars still shine. Unfortunately, though, Kaku sometimes stumbles when he strays beyond physics. Errors creep into his historical summaries (Copernicus wrote his astronomical treatise well before his deathbed), and analogies sometimes fall flat: he states that plucking a musical string harder produces a different note (it just becomes louder). His final chapter looks for meaning in the structure of the cosmos, seeking a compromise between the Copernican principle (we are not special) and the anthropic principle (we can hardly be accidental). Ambitious and thought-provoking. (Kirkus Reviews)