PHYSICISTS DON'T MUCH LIKE GETTING UP EARLY, but they packed promptly into an 8:00 a.m. gathering of the American Physical Society in Washington last week. They were drawn, fittingly enough, by rumors of revelations about the very first dawn, and they were rewarded with dramatic news.
NASA's Cosmic Background Explorer satellite -- COBE -- has found something astronomers have been seeking for nearly 30 years: an almost imperceptible pattern of warm and cool patches in the cosmic microwave background radiation, the oldest light in the cosmos. The radiation was created only 300,000 years after the Big Bang explosion that began the universe, a time when all of space was hot, dense and incandescently bright. The radiation is still around now, 15 billion years later, cooled far below zero and transformed from visible light to microwaves. Its discovery in the mid-1960s confirmed the Big Bang as the premier theory of the universe. The theory also says the temperature of this background radiation must vary from spot to spot in the sky. The variations come from areas of higher and lower density in the universe at that time; without density fluctuations then, there could be no galaxies -- and no humans -- today.
Failure to find the variations until now had understandably made scientists a little nervous. Humans and galaxies obviously exist, so if COBE didn't see them sooner or later, that meant the Big Bang theory, the foundation of modern astrophysics, could have been in serious trouble. But tiny as the variations are -- 30 millionths of a degree at most -- they are enough to keep the Big Bang alive. Says David Spergel, a Princeton astrophysicist: "This is great stuff."Source
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