Listen Closely: From Tiny Hum Came Big Bang

By James Glanz - New York Times

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 here today.

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," he 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 at Berkeley.

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.

Today, 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.

"We do see two more bumps and wiggles out there," Dr. Ruhl said. "We can move to the question of, `What do these bumps and wiggles tell us?' "

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. "This is a very bad day for the competition."

Some other scientists, including Dr. Andrew Lange of Caltech, a leader of the Boomerang group, said the results strikingly showed that cosmologists understood the composition and behavior of the universe in the first few hundred thousand years of its life. It was then that the sound waves were humming through the young cosmos; astronomers believe the microwave background radiation was emitted as the universe cooled below a critical temperature when it was about 400,000 years old.

"We've really been waiting for the other shoe to drop," Dr. Lange said in reference to the lengthy search for the overtones. "What we're confirming for the first time is a very generic prediction of modern cosmology."

Although astronomers said much more detailed observations, including the discovery of further overtones, would be required to define the quantum fluctuations and to verify inflation, the results are likely to be seen as major victories for two scientists in particular.

The first, Dr. Alan Guth of the Massachusetts Institute of Technology, developed the germ of the inflation model in 1980, a theory he has called "the ultimate free lunch" because it shows how the entire universe could have exploded out of nothing and impressed the quantum fluctuations on the cosmos.

The results also provide major support for ideas closely associated with Dr. David Schramm, a Chicago cosmologist who died in a plane crash late in 1997. Dr. Schramm and his colleagues worked out a theory, unrelated to inflation, using trace elements created in the Big Bang explosion to gauge the amount of ordinary matter in the universe.

Those values agree closely with the amounts deduced from the intensity of the sound wave overtones; that intensity is affected by the sloshing of matter in the sound waves' peaks and troughs.

On the other hand, the results also leave cosmologists with some deep and perhaps troubling questions.

For example, the new observations confirm that most of the cosmos seems to be made of so-called dark matter and dark energy, possibly particles or energy lurking somewhere in space but still never detected directly. Dr. Turner, of Chicago, said skeptics might well term that picture "the absurd universe, or the preposterous universe."

Sir Martin Rees, an astrophysicist at Cambridge University, said scientists were left with the question of whether fundamental physical laws would someday explain that strange mixture of ingredients, or whether the precise amounts were a sort of accident of how the universe came into being — something like snowflakes, each of which has a hexagonal symmetry but carries a pattern that is otherwise unique.

"It may well turn out that the underlying laws do not give us these numbers, any more than they give the detailed pattern of a snowflake," Sir Martin said.