Evidence spotted for the universe's early growth spurt

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NEW YORK -- Researchers say they have spotted evidence that a split-second after the Big Bang, the newly formed universe ballooned out at a pace so astonishing that it left behind ripples in the fabric of the cosmos.

If confirmed, experts said, the discovery would be a major advance in the understanding of the early universe. Although many scientists already believed that an initial, extremely rapid growth spurt happened, they have long sought the type of evidence cited in the new study.

The results reported Monday emerged after researchers peered into the faint light that remains from the Big Bang of nearly 14 billion years ago.

The discovery "gives us a window on the universe at the very beginning," when it was far less than one-trillionth of a second old, said Arizona State University theoretical physicist Lawrence Krauss, who was not involved in the work. "It's just amazing," he said. "You can see back to the beginning of time."

Monday's findings were announced by a collaboration that included researchers from the Harvard-Smithsonian Center for Astrophysics, the University of Minnesota, Stanford University, the California Institute of Technology and NASA's Jet Propulsion Laboratory. The team will submit its conclusions to a scientific journal this week, said its leader, Harvard's John Kovac.

Johns Hopkins University theoretical physicist Marc Kamionkowski, who also did not participate in the research, said the finding is "not just a home run. It's a grand slam." He and other experts said the results must be confirmed by other observations, a standard caveat in science.

Right after the Big Bang, the universe was a hot soup of particles. It took about 380,000 years to cool enough that the particles could form atoms, then stars and galaxies. Billions of years later, planets formed from gas and dust orbiting stars. The universe has continued to spread out.

Arizona State's Mr. Krauss said he thinks the new results could rank among the greatest breakthroughs in astrophysics over the past 25 years, such as the Nobel prize-winning discovery that the universe's expansion is accelerating.

Astronomers scanned about 2 percent of the sky for three years with a telescope at the South Pole, where the air is exceptionally dry. They sought a specific pattern in light waves within the faint microwave glow left over from the Big Bang. The pattern has long been considered evidence of rapid growth, known as inflation. Mr. Kovac called it "the smoking-gun signature of inflation."

The researchers say the light-wave pattern was caused by gravitational waves, which are ripples in space and time. If verified, the new work would be the first detection of such waves from the birth of the universe, which have been called the first tremors of the Big Bang.

Mr. Krauss cautioned that the light-wave pattern might not be a sign of inflation, although he stressed that it's "extremely likely" that it is. The pattern is "our best hope" for a direct test of whether the rapid growth spurt happened, he said.

The Massachusetts Institute of Technology's Alan Guth, a creator of the idea of inflation, said the findings already suggest that some ideas about the universe's rapid expansion can be ruled out. It had not been clear whether the light-wave pattern would be detectable even if inflation really happened, he said, but luckily, "nature is cooperating with us, laying out its cards in a way that we can see them."

University of Pittsburgh professor Arthur Kosowsky is a cosmology researcher and a cosmic microwave background radiation expert. He and two fellow researchers, Johns Hopkins' Mr. Kamionkowski and Albert Stebbins of Fermi National Accelerator Laboratory in Batavia, Ill., predicted the polarization signal in a highly cited 1997 paper. Two others in the field, Uros Seljak of the University of California-Berkeley and Mathias Zaldarriaga of the Institute for Advanced Study in Princeton, N.J., independently predicted it.

In an interview Monday, Pitt's Mr. Kosowsky said of the Big Bang report: "The bottom line -- this is the first time we have likely obtained any information about when the universe was so young and so hot and dense. It was so hot at that early moment that the energies of the particles were 10 trillion times higher than the energies we create at the Large Hadron Collider [on the Franco-Swiss border near Geneva], which discovered the Higgs boson last year.

"In other words, the signal is a glimpse into physics at such extreme scales that we will never be able to probe them directly. And it shows that at those scales, there is new physics that is not explained by the current standard model of physics."

Mr. Kosowsky said he and his Pitt graduate students will work on confirming this signal and discovering more about it in their future work. He is associated with an experiment that uses the Atacama Cosmology Telescope in the Atacama Desert of Chile.

Post-Gazette staff writer Sean Hamill contributed.

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