Two teams of cosmologists have released new findings about the nature of the universe in its infancy. Their spectacular images of the cosmic microwave background, taken with instruments operating from Antarctica, reveal the strongest evidence to date for the theory of inflation, the leading model for the formation of the universe.
The announcement represents the first release of data from the Degree Angular Scale Interferometer, a 13-element ground-based instrument operating since last year at the National Science Foundation's (NSF) Amundsen Scott South Pole Station.
Scientists also released similar results from further analysis of data from the Balloon Observations of Millimetric Extragalactic Radiation and Geophysics, or BOOMERANG, project, obtained in 1998 and first reported last year.
"These spectacular results represent a payback from the significant national investment in research in the polar regions," said Karl Erb, director of the NSFs Office of Polar Programs. "The Antarctic environment provides exceptional clarity for astrophysical observations, and the U.S. Antarctic Program provides unmatched support for world-class research."
Both analyses, unveiled at meetings of the American Physical Society in Washington, D.C., support the model that the universe experienced a tremendous spurt of growth shortly after the Big Bang. Cosmologists believe the structures that formed in the very first moments of the cosmos left their imprint as a very faint pattern of variations in the temperature of the cosmic microwave background, the radiation left over from the intense heat that filled the embryonic universe during the initial growth spurt. Some 12 billion to 15 billion years later, these temperatures have become detectable from Earth with highly sensitive instruments.
"With these new data, inflation looks very strong," said John Carlstrom, professor of astronomy and astrophysics at the University of Chicago and lead scientist of the Degree Angular Scale Interferometer. "It's always been theoretically compelling. Now it's on very solid experimental ground."
Multiple teams supported by NSF, including the two teams operating from the polar region, have probed the cosmic microwave background for these minute temperature variations. Two other teams using instruments in the continental United States also released data.
"This is an outstanding example of how NSF supports multiple scientific projects, leading to rapid, new results," said NSF senior science associate Morris Aizenman. "It took more than a decade to get the initial observations of the cosmic microwave background with the [Cosmic Background Explorer, or COBE] satellite, and in only a few short years, the progress in sharpening those observations has been truly astounding."
The teams used independent methods and two different technologies to obtain detailed observations of the cosmic microwave background. The observations have provided so much data that new methods had to be invented to analyze them. As the data analyses continue, they are providing precise measurements of parameters that cosmologists have long used to describe the early evolution of the universe but in the past could only illustrate with models.
NASA's COBE satellite provided the first detailed images of tiny variations in the cosmic microwave background radiation in 1992. Last year, the BOOMERANG team published the first high-resolution images of the phenomenon, obtained with a telescope suspended from a balloon that circumnavigated the Antarctic at an altitude of almost 37 kilometers (120,000 feet). A third team obtained high-resolution images with the Millimeter Anisotropy Experiment Imaging Array (MAXIMA), flown with a high-altitude balloon over the continental United States.
The intricate images from the independent projects showed the very beginnings of structure in the universe and provided evidence for the prediction that the universe was "flat," a term that refers to the curvature of space.