Tod Lauer is starting to feel more than a little fed up with his fellow astronomers. Not long ago, Lauer and his close friend and collaborator Marc Postman, of the Space Telescope Science Institute, in Baltimore, Maryland, announced the results of a telescopic study they had been working on for more than a year. The young scientists reached the astonishing conclusion that rather than expanding outward in a stately fashion like the rest of the universe, a collection of many thousands of galaxies, including our own and spanning a billion light-years or so, may be speeding en masse toward a point somewhere in the direction of the constellation Virgo.
Yet rather than try to assimilate this new finding, most of their colleagues are proclaiming that it must be a mistake. No one can explain what Lauer and Postman might have done wrong, despite strenuous efforts to do so. The analysis is incorrect, they say, simply because it doesn't fit in with any existing theory of how the cosmos works. "Listen," fumes Lauer, who is stationed at the National Optical Astronomy Observatories in Tucson, Arizona, "we knew this was a shocking result. That's why we spent over a year trying to debunk it ourselves before we went public. If anyone can present a good argument why it's wrong, we'll listen."
Allan Sandage is angry at his astronomical brethren too, but his beef is just the opposite of Lauer's. The Carnegie Observatories astronomer has spent much of his nearly 40-year career trying to measure the age of the universe; it's a task he inherited from his mentor Edwin Hubble, the legendary scientist who discovered that the universe is expanding and that galaxies exist beyond the Milky Way. For decades, Sandage's results have suggested that the cosmos is 15 billion to 20 billion years old or thereabouts. That fits beautifully with cosmological theories-but almost nobody believes him anymore. Instead they're listening to a young whippersnapper named Wendy Freedman, who happens to work just down the hall from Sandage at the Carnegie's center in Pasadena, California. Freedman and a group of colleagues have lately used the Hubble Space Telescope to peg the age at somewhere between 8 billion and 12 billion years-which would make the cosmos 2 billion years younger than some of the stars it contains. "Our opponents," says Sandage bitterly, "are so wonderfully kind. They say we don't have anything to stand on."
Tension between theory and observation is part of the normal course of science. It keeps both sides honest, and, at those rare times in history when the two lock horns irreconcilably, it can lead to nothing less than a full-fledged scientific revolution. Without such clashes, in fact, we'd still believe that the sun orbits Earth and that disease is caused by evil spirits.
But what's happening these days in cosmology-the study of the universe-verges on the bizarre. Astronomers have come up with one theory-busting discovery after another, hinting that a scientific revolution may be close at hand. At stake are answers to some of the most fundamental questions facing humanity: What is the origin of the universe? What is it made of? And what is its ultimate destiny?