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William Atkins
Wednesday, 07 February 2007 22:03
Currently, cosmologists can only go back hundreds of thousands of years after the Big Bang, the theorized explosive beginning of our universe. However, new research being performed by U.S. physicist Richard Easther (Yale University, New Haven, Connecticut) and Spanish physicist Juan García-Bellido (Independent University of Madrid, Spain) may produce direct evidence of the universe only a miniscule fraction of a second after it was created.
Theoretical scientists have calculated that gravitational waves could have been generated at the end of a period of rapid expansion that occurred roughly a trillionth of a second (and lasted only about one-billionth-trillionth-trillionth of a second) after the initial Big Bang explosion. These calculations were possible in part due to the prediction of such waves by German-American physicist Albert Einstein through his general theory of relativity.
The violent period of expansion (rapid inflation) of the universe within that tiny fraction of a second was so large and disruptive to the universal fabric of space-time that cosmologists believe it can still be observed today. That is the goal of these scientists: to glimpse and measure those gravitational waves that are still theoretically possible to observe even today—over 13.7 billion years later (the generally accepted age of the universe).
If these physicists succeed in their venture, as Easther said in the February 3, 2007 issue of Science News, “Anyone who sees a gravitational wave is going to be just enormously excited about that.”
These gravitational waves hopefully will be detectable sometime in the next ten years by a pair of upgraded gravitational-wave detectors. The two linked detectors are operated through the Laser Interferometer Gravitational-Wave Observatory (LIGO) at two U.S. sites in Hanford, Washington (LIGO Hanford Observatory, LHO, operated in conjunction with Massachusetts Institute of Technology) and in Livingston, Louisiana (LIGO Livingston Observatory, LLO, operated in conjunction with California Institute of Technology).
The two groups of physicists used different mathematical models to predict the gravitational waves. The conclusions of García-Bellido and his colleagues will appear in a future issue of Physical Review Letters and the results of Easther and his colleagues will appear in an issue of Journal of Cosmology and Astroparticle Physics.
The Home Web page of LIGO is: http://www.ligo.caltech.edu/.
Additional information about early-Big Bang gravitational waves can be found at: http://www.aip.org/pnu/2007/split/809-1.html.
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