Author: Martin Bojowald
File Type: epub
In 2000, Martin Bojowald, then a twenty-seven-year-old post-doc at Pennsylvania State University, used a relatively new theory called loop quantum gravitya cunning combination of Einsteins theory of gravity with quantum mechanicsto create a simple model of the universe. Loop quantum cosmology was born, and with it, a theory that managed to do something even Einsteins general theory of relativity had failed to doilluminate the very birth of the universe.Ever since, loop quantum cosmology, or LQC, has been tantalizing physicists with the idea that our universe could conceivably have emerged from the collapse of a previous one. Now the theory is poised to formulate hypotheses we can actually test. If they are verified, the big bang will give way to the big bounce. Instead of a universe that emerged from a point of infinite density, we will have one that recycles, possibly through an eternal series of expansions and contractions, with no beginning and no end.Bojowalds major realization was that unlike general relativity, the physics of LQC do not break down at the big bang. The greatest mystery surrounding the origin of the universe is what cosmologists call the big bang singularitythe point at the beginning of the universe, prior to the existence of space and time, when gravity, along with the temperature and density of the universe, becomes infinite. The equations of general relativity cant cope with such infinities, and as a result big bang theory has never been able to give any explanation for the initial condition of our universe, succeeding only in describing and explaining the evolution of the universe from that instant onward. Bojowalds theory takes us right up to the first moment of the universeand then back, even before the big bang itself.From the Hardcover edition.From Publishers WeeklyStarred Review. If its possible to write a literary treatment of cutting-edge cosmology, groundbreaking physicist Bojowald has done it, complete with illustrations of abstract sculpture and quotes from thinkers as diverse as Nietzsche, Schopenhauer, Charles Dickens, and Joseph Heller. Bojowald, a professor of physics at Penn State, explores loop quantum theory, an idea he developed as a postdoctoral student in 2000, to fill in the gaps left by 20th-century physics. Despite advances like relativity theory, curved space, and quantum theory, physics falters when it comes to explaining what happened before the Big Bang, when time, space, matter, and energy were all shrunk into a bizarre entity called a singularity, where math and logic as we know them failed. Later, string theory, with its extra dimensions and elegant equations, offered promise, but only with loop quantum cosmology were physicists able to see the universe be born, expand, shrink, and be reborn, over and over again. Bojowald largely avoids mathematics for accessibility, but that can leave his writing dense with rigor as he strives to cover the Whole Story. Readers willing to meet his challenge will find a fascinating new universe revealed by his enthusiastic firsthand approach. 37 illus. (Nov.) (c) PWxyz, LLC. From BooklistIn theoretical physics, gravity can be an intractable problem. At extreme values prevalent near the big bang or black holes, general relativity cant accommodate it. String theory purports to be a solution, but not all physicists are on the string bandwagon. One such recalcitrant, Bojowald champions a rival theory called loop quantum gravity, which he here valiantly presents to the nonmathematical. If his explanation daunts some science readers, its implications will be sufficiently clear and exciting to pull them through his text, because those involve the start of the big bang and the interior of a black hole. Notionally, each one is a singularity as Bojowald describes the failure of mathematics when energy density goes to infinity and space collapses to zero volume. Loop quantum gravity offers an escape from these terrifying places by acting like a quantum-mechanical Atlas who holds space open just enough so that physicsthe universecan continue to exist. Complex but comprehensible, Bojowalds treatment of loop quantum gravity should compete with popular string-theory titles such as Endless Universe (2007), by Paul Steinhardt and Neil Turok. --Gilbert Taylor