Researchers from Carnegie Mellon University, using aNational Science Foundation (NSF) microwave telescope inAntarctica, have made a crucial measurement of cosmic backgroundradiation that may help science to settle a fundamental questionof whether the universe will expand forever or collapse back uponitself.
Scientists measured the dimensions of extremely distant gasclouds with the Viper Telescope, operated by the Center forAstrophysical Research (CARA) in Antarctica at NSF's AmundsenScott South Pole Station.
Jeffrey Peterson, a Carnegie Mellon astrophysicist and thelead scientist on the Viper project, announced the findings onDec. 18 in Paris, France at the Symposium on RelativisticAstrophysics. The biennial meeting attracts the world's foremostastronomers and astrophysicists.
"These findings indicate that the material of the universewas given just the right kick by the Big Bang to expand forever,never collapsing, but also never becoming so dilute that gravitycan be ignored," according to Peterson. "This delicate balanceis hard to understand unless inflation theory, or something akinto it, is correct."
Viper is used to make images of the faint structure, ananisotropy, seen in the sky. Astrophysicists widely accept thatif the expansion of the universe were slowing, the glowing cloudsof gas observed with Viper would be, in astronomical terms,relatively close by and would measure as much as one-half degreeof arc across the sky. The discovery announced this week -- thatthe size of extremely distant gas clouds is, indeed, one-halfdegree on the sky -- indicates that the expansion of the universeis slowing at just the rate predicted by inflation theory.
Inflation theory holds that just after the Big Bang, as theuniverse expanded and cooled, it passed through a criticaltemperature, currently thought to be 100 billion degrees -- whichchanged the character of the laws of physics. As the protouniverse passed through this critical temperature threshold,there was an enormous release of energy, which caused theuniverse to "inflate,' or to dramatically increase in size.
This inflation process would have caused the universe toexpand with a precise "escape velocity," which would provide anexplanation for the Viper findings. The newly releasedmeasurements indicate that the universe has just such an escapevelocity, Peterson stressed.
The anisotropy measurement is just a small part of the datacollected from the telescope, which provides a snapshot of theuniverse as it was 300,000 years after the Big Bang, thecataclysmic event that set in motion the forces that createdtoday's universe.
Previous cosmic background telescopes have been smaller thanViper and have not been able to focus in fine enough detail tomeasure the clouds as viper can. However, the CARA group's workwith these earlier prototypes was critical to the new discovery.Karl Erb, the director of NSF's Office of Polar Programs, said"This advance is a fitting testament to the vision and dedicationof the CARA scientists whose pioneering work proved that theSouth Pole is an ideal site for these delicate measurements."The two-meter Viper telescope began operation only last February.
Further observations by Viper and other telescopes underdevelopment by CARA's member institutions are planned to verifythe newly released result.
Materials provided by National Science Foundation. Note: Content may be edited for style and length.
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