Reprinted from the Tacoma News Tribune - Monday, April 30, 2001
Astronomers think they hear echo of the big bang
PRIMORDIAL GAS: Scientists find traces of waves they think date from birth of the universe
By JAMES GLANZ
WASHINGTON Two detectors in Antarctica have discovered minute patterns in a glow from primordial gases, possible traces of the cosmic match that ignited the Big Bang and led to the creation of the universe 14 billion years ago, astronomers announced on Sunday.
The patterns, astronomers said, were probably created by microscopic processes energy fluctuations at the quantum scale that were at work when the universe was a tiny fraction of a second old and smaller than a human fist.
The new observations do not see the quantum fluctuations directly, but instead have found traces of colossal waves, much like sound waves, that the fluctuations probably set in motion, roiling the young universe.
The results rest on the most detailed observations ever made of a glow from the hot gases of the early universe. That glow, called cosmic microwave background radiation, carried an imprint of those waves to the detectors on Earth.
The news comes as a relief for astronomers, some of whom started to worry last year that their basic picture of the origins of the universe might be flawed, after detailed observations failed to find the wave patterns.
"We see the structure of the universe in its infancy," said Dr. John Carlstrom, a University of Chicago astrophysicist who leads the team operating the Degree Angular Scale Interferometer, or DASI (pronounced daisy), a microwave detector at a South Pole research station operated by the National Science Foundation. Dr. Michael Turner, a cosmologist at the University of Chicago who was not involved in the measurements, said that the precise time the fluctuations took place remained to be determined by future measurements, but that the process was likely to have taken place in a fraction of a second comparable to a decimal point followed by 32 zeros and a 1.
"We are living in the most exciting time ever in cosmology," Turner added.
Besides DASI, which also involved astronomers at the California Institute of Technology, the announcement today included the so-called Boomerang team. This group flew a balloon-borne detector around Antarctica, and includes astronomers from the United States, Italy, Canada and Britain. Antarctica is excellent for such observations because the air is thin and dry and does not strongly absorb microwave radiation.
Dr. John Ruhl of the University of California at Santa Barbara presented results today for the Boomerang team. The announcements took place at a meeting of the American Physical Society.
The Antarctica studies were buttressed today when another group of researchers reported that they had made less distinct observations of the wave patterns from the United States. That team, called Maxima, includes astronomers at the University of Minnesota and the University of California.
The leading theory of how the universe could have exploded out of the primordial nothingness, known as the theory of inflation, predicts that the quantum fluctuations should have rattled the universe in such a way that it resonated like a vast organ pipe, with one main tone, or wavelength, and a series of overtones or harmonics.
Last year, the Boomerang team detected the main tone but found no clear evidence for the overtones, raising the possibility that the inflation theory could be wrong. Since much of the information about the fluctuations, like their relative intensity and spectrum, would reside in the characteristics of the overtones, those results raised the prospect that few remnants of the initial spark might be found.
On Sunday, the three teams announced that they had seen two of the overtones for the first time. In musical terms, the observations saw the first two harmonics above the main tone.
Dr. Max Tegmark, a cosmologist at the University of Pennsylvania, said that while the new results were still far from absolute proof of the inflation theory, their agreement with the theory was uncanny and would cast doubt on alternative models. "It's even scary that things agree this well," he said.