PASADENA, Calif. — The first detailed images of the embryonic universe suggest the cosmos will expand forever and not someday collapse upon itself, according to new research on the Big Bang.
Observations from a balloon-borne telescope that circumnavigated Antarctica largely match predictions and suggest scientists are on the right track in their understanding of the earliest moments of the universe, its composition and ultimate fate.
"It is an incredible triumph of modern cosmology to have predicted their basic form so accurately," said Andrew Lange of the California Institute of Technology and U.S. team leader of the $4 million international project dubbed "Boomerang."
The telescope carried aloft for nearly 11 days in 998 measured minute variations in the cosmic microwave background radiation, a faint glow that fills the sky in all directions and is believed to be the fading remnants of the Big Bang 12 billion to 15 billion years ago.
The images reveal the large-scale geometry of the cosmos and the underlying structures that were the precursors of today's clusters of galaxies.
"We are seeing something like the seeds of creation of the structure of the modern universe," said Harley Thronson, senior science manager for NASA's space science office. NASA, the National Science Foundation and the Department of Energy participated in the project along with four nations and 16 universities.
In the first results, published this week in the journal Nature, scientists said the ripple patterns precisely match the scenario of a "flat" universe in which parallel lines never cross.
The findings rule out the possibility that the fabric of space-time is curved onto itself like a sphere or bent outward like a saddle. It also means that the universe will not collapse in a big crunch.
"We are really demonstrating that it's flat, and we are demonstrating that it will expand forever," said Italian team leader Paolo deBernardis of the University of Rome, La Sapienza.
The flat universe also fits the so-called inflationary theory that the universe underwent a rapid expansion in a fraction of a second after its birth.
"It's confirmation of the prediction of our best theory of what caused the structure of the universe," said Alan Guth, a Massachusetts Institute of Technology physicist who first proposed the theory in 1980. "It means that there's a very good chance that we're on the right track."
Measurements of the small ripples indicate the large-scale geometry of the universe, which the general theory of relativity says is determined by the total amount of matter and energy in the cosmos.
The Boomerang data also reveal hundreds of complex structures that represent the effects of the density variations in the early universe.
They are the seeds in which clusters of galaxies would form, said Boomerang scientist John Ruhl, a physicist at the University of California, Santa Barbara.
Scientists hope to further refine the data to better quantify the nature of the matter that makes up the cosmos.
"What we will get is a census of the universe but without knowing what kind of things make up the population," said Edward Wright, an astronomer at the University of California, Los Angeles.
Shortly after the Big Bang, the universe was made of a fog of subatomic particles and radiation hotter than the surface of the sun. It was so dense that photons — the smallest units of energy — bounced off the primordial soup.
As the universe expanded and cooled, normal matter formed and the photons no longer scattered but moved freely through space. Boomerang analyzes variations that echo the final scattering, roughly 300,000 years after the Big Bang.
The background radiation, which contributes to snow on earthly television sets, was first detected in 1965. But the tiny ripples or variations were not found until 1991 by NASA's Cosmic Background Explorer satellite.
The satellite covered the entire sky but had a very coarse view, far too rough for scientists to see enough detail to discern complex structures. The Boomerang experiment, by comparison, covered 2.5 percent of the sky but with a resolution 35 times higher.
Scientists with the Boomerang project (it stands for Balloon Observations of Millimetric Extragalactic Radiation and Geophysics) plan another flight in search of even greater detail. Two satellites will be launched in coming years that will analyze the entire sky with high precision and detail.