Telescope reveals early universe

With Antarctica's Mount Erebus as a backdrop, the Boomerang telescope prepares for launch as a balloon is inflated to carry it

Detailed images suggest scientists
on right track with theories of cosmos

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A 'flat' universe
Taking a census of the cosmos

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From staff and wire reports

PASADENA, California -- Images from a telescope over Antarctica has revealed scientific evidence that supports long-held theories about the early universe. The images give astronomers and cosmologists information about the universe before stars, planets and galaxies existed.

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The first observations largely match theorists' predictions and suggest scientists are on the right track in their understanding of the earliest moments of the cosmos, its composition and ultimate fate.

"It is an incredible triumph of modern cosmology to have predicted (the cosmos') basic form so accurately," said Andrew Lange of the California Institute of Technology and U.S. team leader of the international project dubbed Boomerang. (It stands for Balloon Observations of Millimetric Extragalactic Radiation and Geophysics.)

The sensitive telescope, attached to a balloon, floated over Antarctica for 11 days in late 1998. Scientists launched the balloon because they wanted to get images of the cosmic microwave background, which is radiation left behind from the early universe. They chose Antarctica because the wind patterns allowed the balloon to stay up longer, permitting the telescope to gather more information.

"The universe was just a soup then of ionic matter and radiation," said James Bock, a research scientist working with the Boomerang project at the Jet Propulsion Lab in Pasadena.

The telescope made images of minute details and changes within that radiation, which is believed to be the fading remnants of the big bang 12 billion to 15 billion years ago.

"We're looking at the universe in its embryonic form, when it looked vastly different than it did today and well before when the first star or galaxy formed," Lange said.

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.

In the first results, scientists said the ripple patterns precisely match the scenario of a "flat" universe in which parallel lines never cross. That means the universe is two-dimensional, like a piece of paper.

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 some day collapse onto itself in a big crunch.

Those ripple patterns that suggest a two-dimensional universe provide scientific evidence of the long-held theory of inflation -- 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."

Scientists also hope to refine the data further 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. The Boomerang project 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, providing sharper, more detailed images.

The 1991 satellite "gave what you would call a very blurry image of the whole sky," Wright said. "And the Boomerang experiment has given a very much less blurry image of a part of the sky."

Scientists with the Boomerang project 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.

"It's amazing how much we do understand, but there are some very, very basic ones we don't understand like what most of the universe is made out of," said MIT's Guth. "There is certainly a good chance that questions like that will get answered in the next five to 10 years."