By the faint cosmic glow of the oldest known light, physicists say they have found evidence that the universe grew to astounding proportions in less than the blink of an eye.
In that trillionth of a second after the big bang, the universe expanded from the size of a marble to a volume larger than all of observable space through a process known as inflation. At the same time, the seeds were planted for the formation of stars, galaxies, planets and every other object in the universe.
"It's giving us our first clues about how inflation took place," said Michael Turner, assistant director for mathematics and physical sciences at the National Science Foundation. "This is absolutely amazing."
Researchers found this long-sought "smoking gun" evidence by looking at the cosmic microwave background, the oldest light in the universe. The light was produced when the universe was about 300,000 years old - a long time ago, but still hundreds of millennia after inflation had done its work.
Even so, the pattern of light in the cosmic microwave background offers clues about what came before it, just as a fossil tells a paleontologist about long-extinct life. Of special interest to physicists are subtle brightness variations that give images of the microwave background a lumpy appearance.
Physicists presented new measurements of those variations during a news conference Thursday at Princeton University. The measurements were made by a spaceborne instrument called the Wilkinson Microwave Anistropy Probe, or WMAP, launched by NASA in 2001.
"It amazes me that we can say anything at all about what transpired in the first trillionth of a second of the universe," said Charles Bennett, a Johns Hopkins University physicist who presented the research along with Lyman Page and David Spergel, both of Princeton.