Alan Guth’s career was up in the air. As an ambitious postdoc at Cornell University in 1978, Guth was looking for a way to contribute to his field of particle physics, but his research had attracted little interest. He also needed to find a permanent job to support his wife, Susan, and baby, Larry. But his job search hadn’t gone well either.That fall a trio of cosmologists, or early-universe theorists, had won the Nobel Prize in physics. Soon, discussions about the origin of the universe and especially the big bang theory-the idea that the universe began with an explosion and that all matter has been moving outward ever since-were buzzing in the halls of academe and among the general public. So when a cosmologist came to speak at Cornell, Guth ‘69, SM ‘69, PhD ‘72, went to hear what he had to say. The lecturer, Robert Dicke, spoke of, among other things, a complex cosmological problem scientists had been unable to solve. “It certainly piqued my interest,” Guth says. “Dicke’s lecture seemed to point to the conclusion that traditional big-bang theory was leaving out something important.” Two years later, in the course of his research in an entirely different area, Guth happened upon the missing piece.
He introduced his explanation in 1981, calling it “inflation.” Since then the theory has garnered much attention. In the years since its appearance, Guth’s original paper has been cited in more than 2,000 publications, and last fall its author received the prestigious Dirac Medal, which many observers consider a precursor to a Nobel Prize. Today cosmologists are calling Guth’s idea a new paradigm, one of the last half-century’s few supremely influential theories of the universe.