For immediate release: December 13, 2002
For more information, contact Susan Griffith, 216-368-1004 or sbg4@po.cwru.edu

CLEVELAND—More than 10 billion years ago the Big Bang gave birth to our universe. Over recent months, researchers in a National Science Foundation-funded project at the Amundsen-Scott South Pole Station captured some of the earliest and most detailed baby pictures of the universe ever recorded as it rapidly began to cool around the age of 400,000 years old and evolve into the universe we see today.

Research by a CWRU physicist and others at the South Pole has produced this image of the universe at about 400,000 years old.

By measuring the Cosmic Microwave Background (CMB) radiation with powerful and sensitive new instruments, this early remnant of universe formation provides Case Western Reserve University physicist John Ruhl, a principal investigator in the CMB study, and other research team members with further evidence of a new universe model in which strange "dark energy" comprises 65 percent of the universe and that some 30 percent of an unknown form of "dark matter," while planets, stars and other "normal matter" fill the rest of space. This makeup of the universe also helps explain why the expansion of the universe continues appears to be accelerating, while normal matter would slow the expansion as time passes.

The NSF announced Friday, December 13 the new research findings that have been submitted for publication in Astrophysical Journal.

Ruhl and William Holzapfel from the University of California at Berkeley headed the project that developed the Arcminute Cosmology Bolometer Array Receiver (ACBAR) attached to the 2.1-meter Viper telescope, built by collaborators at Carnegie Mellon University, for research at the South Pole. Both instruments were developed through support of the NSF Center for Astrophysical Research in Antarctica. The new technology enabled the researchers to make very sensitive images of the early universe over months of observing from the South Pole. These images give details of the behavior of the plasma of which the early universe was made. Ruhl describes this plasmas as being "very similar to the plasma that makes up our Sun," where atoms cannot form-instead, they are broken into separate electrons, protons and heavier nuclei.

"We're doing cosmic archeology with ACBAR in an effort to piece together the early universe," says Ruhl. Antarctica provides an ideal site to observe the early universe, because Antarctic conditions provide a thin atmosphere with little water vapor. This gives scientists an excellent view of the electromagnetic spectrum at the wavelengths where the CMB is bright, in millimeter to microwave portions of the spectrum.

"For our observations, the South Pole is as close as you can get to space while having your feet planted on Earth," adds Ruhl.

ACBAR is an array of 16 detectors that create images of the sky in three mm-wavelength bands near the peak in the brightness of the CMB. To reach its high level of sensitivity, the receiver is cooled by a special refrigerator to a temperature near absolute zero (-459 Fahrenheit). As temperatures at the South Pole plunged as low as -100 Fahrenheit during Antarctica's winter, Matthew Newcomb, a researcher on the team, made observations for eighth months during the last two cold winters in Antarctica.

Researchers for years have searched for evidence to support the present of dark energy, first mentioned by Albert Einstein in 1929 in his theory of general relativity.

"With ACBAR, we're looking at new aspects of the CMB, and that adds to our confidence that these very bizarre things-dark matter and dark energy-actually exist. We don't understand them yet, so there's a new frontier to explore," says Ruhl.

Other researchers collaborating in the CMB project are from Carnegie Mellon University, the California Institute of Technology, Jet Propulsion Laboratory and Cardiff University in the United Kingdom.

Four years ago, the researchers began constructing and installing the array at the South Pole. Over two, six-month periods, ACBAR collected the data that led to these images of the early universe.

For more informationon ACBAR, including additional maps and pictures, go to http://cosmology.berkeley.edu/group/swlh/acbar/press/.

–CWRU–

 

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