It was a coal-black night in March, the kind astronomers like best. At Arizona's Kitt Peak National Observatory, Princeton Astrophysicist Edwin Turner pointed the 158-in. reflecting telescope first at one distant pinpoint of light in the sky, then at a neighboring one. A few hours later, studying the results of his night's labors, Turner could hardly believe his eyes. "It was a big surprise," he says. "But a big surprise is always a clue you might be on the track of something."
Something indeed. After analyzing the light from the distant sources, Turner and seven other scientists concluded that they had...