When I started teaching college in 1964, the required reading for my general studies science course included two articles by two prominent physicists published in Scientific American eight years previously. George Gamow, a principal architect of the big bang theory, made the case for a universe that began billions of years ago as an explosion from an infinitely dense and infinitely small seed of energy. Fred Hoyle, stalwart champion of the steady state theory, took the stand for an infinite universe with no beginning and no end, in which matter is continuously created in the space between the galaxies.
Both theories explained the outward rush of the galaxies discovered by Vesto Slipher, Edwin Hubble and Milton Humason in the first decades of the century. Both theories had strengths and weaknesses. For example, the big bang successfully accounted for the known abundances of hydrogen and helium in the universe but posited an embarrassing beginning that could not be explained. The steady state theory avoided the stumbling block of a universe that seemed to come from nowhere but replaced it with many little unexplained beginnings (those particles of matter appearing continuously from nothing). Yet the big bang theory made one prediction that was testable: if the universe began in a blaze of luminosity, a degraded remnant of that radiation should still permeate the cosmos, and the precise spectral distribution of this microwave-frequency background could be calculated.
Meanwhile, entirely independently, two radio astronomers at Bell Labs in New Jersey, Robert Wilson and Arno Penzias, were trying to find the source of an annoying hiss in their microwave antenna that seemed to come equally from all parts of the sky. The hiss turned out to have precisely the characteristics predicted by the big bang cosmologists.
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For the first time in history, the human mind had constructed a creation story that could be tested empirically. With the discovery of the cosmic microwave background radiation, the big bang delivered a knockout blow to its steady state competitor.
It's a wonderful story, and it deserves a master storyteller. Simon Singh--a physicist with established credentials as a science popularizer--is up to the task. His previous books, Fermat's Enigma and The Code Book, became international best-sellers. Singh weaves the many threads of the story skillfully together, beginning with the cosmological speculations of the ancient Greeks and ending with the thorny contemporary question, "What came before the big bang?" His tale begins slowly, but only because we know so little about the personal lives of the early players. Singh really gets up to speed as we enter the 20th century, with its lively cast of strong personalities tussling with the universe and with one another.
Two great historical debates lie at the heart of the book. The first concerned whether the spiral nebulae, catalogued throughout the 19th century, are part of our own Milky Way Galaxy, and therefore relatively near, or other "island universes" far away. Resolving this debate meant finding a reliable way to measure the distances to the nebulae. Singh ushers onstage two giants of 20th-century astronomy, Harlow Shapley and Edwin Hubble, who anchored opposite sides of the nebula debate. He also gives star turns to astronomers who deserve to be better known, such as Annie Jump Cannon and Henrietta Leavitt. Telescopes played a leading role in the debate, most notably the 100-inch Hooker Telescope on Mount Wilson and the 200-inch Hale reflector on Mount Palomar, both in California. These instruments enabled astronomers to resolve the nebulae into stars, which provided the necessary distance indicators.
The spiral nebulae are indeed other Milky Ways. Once the nebula debate was resolved, Hubble recognized the expansion of the universe, and a second great debate came to the fore: big bang vs. steady state. Big ideas and big egos were at stake. Gamow and Hoyle, in particular, squared off against each other, even in the pages of this magazine. [break]
Then came the discovery of the cosmic background radiation in the mid-1960s by the Bell Labs radio astronomers. No sooner had I introduced my students to the most contentious cosmological debate of the 20th century than the universe whispered the resolution.
Singh spins out the drama with verve and wit. We meet scientists who are shy and retiring and others with a flair for contention, epic discoveries made serendipitously and beautiful theories shot down by intractable facts, a pooch named Kepler and a persistent pigeon that made its home in the Bell Labs telescope. This is a perfect book for anyone who wants to know what science is all about.
