American Scientist

The Little Book of the Big Bang: A Cosmic Primer. Craig J. Hogan. 192 pp. Springer-Verlag, 1998. $20.

The Big Bang is where all our knowledge and ignorance of the universe meet. We have boldly extended the laws of physics in time and space to come up with a compelling history of the early universe. Ironically, the first few minutes of the Big Bang are better understood than the billion or so years that followed, when gravity sculpted the structures we see around us in space. The Big Bang describes a cauldron of matter and radiation that has left many imprints on the large and cool universe we now inhabit. The success of the hot Big Bang model begs a further series of questions: How did gravity behave and what were time and space like in the first instant? What is the nature of the process by which the universe inflated to its current imposing size? Where did the fluctuations come from that would eventually make it possible for people to exist to reflect on their own origins?

There have been a long line of excellent popularizations of cosmology. George Gamow, one of the first proponents of the model, wrote humorously and elegantly on the subject. For a long time Steven Weinberg's The First Three Minutes was the benchmark—a magisterial treatment although suffused with existential angst. Joe Silk wrote a fine book on the Big Bang. But the dominant force in recent years has been Stephen Hawking. His Brief History of Time was a publishing phenomenon in 15 languages, a book bought for (and possibly unread by) more nieces and nephews than any other in science publishing history. This past year has seen fine new expositions by Sir Martin Rees and Alan Guth.

Craig Hogan's primer on the Big Bang will do well in this company. He has written a book that is both timely and necessary. Timely, because the science of cosmology is progressing rapidly, driven by a tight interplay between theory and new observations. For the first time in 50 years, the basic attributes of the expanding universe—size, age, shape, content—appear to be measurable. Necessary, because most people remain ignorant of the scientific story of creation. The public takes its cue from new reports of difficult observations and seems to view cosmology as a subject on the speculative fringe. Hogan makes the important point that cosmology is a mature discipline. The Big Bang approaches the epistemological status of Darwinian evolution—a simple and profound idea supported by a growing web of evidence. The Big Bang has arrived!

The Little Book of the Big Bang is slim but encyclopedic in its coverage. It surveys space and time from the Planck era to the present. There is a summary of the different manifestations of matter and radiation. The narrative takes the reader back in time, from the nature of the current expansion to the cosmic background radiation to as close to the origin as we can probe. The material is preceded by a delightful introduction by Martin Rees, and it includes a set of informative and artful figures.

The writing is clear and precise. The book is full of dense nuggets of information, almost like cosmology haiku. However, Hogan wears his erudition lightly. Along the way, we find out that the universe contains 10¹⁸⁰ distinct places, that a car with a mass-energy engine would get a billion miles to the gallon and that the laws of quantum mechanics require you to open a door rather than just pass through it. The tone is matter of fact, even blasé. This can work well when describing times and places that are almost impossibly unfamiliar, and it makes a nice counterpoint to the earnest effusiveness of many popular science books.

This is a brave and uncompromising book. The only problem I see is the front-loading of difficult material on forces and interactions. The reader will hear about the Planck length and superstrings in the first few pages of the second chapter, and there is a lot of conceptually challenging material early on. This reductionist cast will appeal to a physicist's sensibility, but the lay reader will find it austere. It might be easier to start with the familiar and the cold and lumpy and work back toward the exotica where intuition fails us. Nevertheless, the inquisitive person will find most of their questions about the universe answered in Hogan's book. And it is a wonderful overview of modern cosmology for a scientist working in another field.

Some years ago I had a disconcerting cultural experience. I took the Moscow subway just before the breakup of the Soviet Union. There were no ads on the walls of the train, and most of the passengers were engrossed in books. Traveling to work, people were actually reading Dostoyevsky and Turgenyev. We can still strive for a world where most people know the gist of cosmology, where straphangers read poetry and The Little Book of the Big Bang.

Well, at least I can dream.