Black holes may bring light to mystery

Finding increases chance that Colo. will get observatory

By Bill Scanlon, Rocky Mountain News (Contact)

Monday, December 3, 2007

An 80-year-old mystery about high-energy cosmic rays may have been solved by Colorado researchers who found answers from an unlikely source - black holes.

And the discovery heightens the chances that a world-class observatory might be built in Lamar in southeastern Colorado.

Colorado researcher Jeff Brack helped lead a team of scientists from 17 countries that found the high-energy particles likely are active galactic nuclei and didn't come uniformly from across the sky. They used information generated by the Pierre Auger Observatory in Argentina, the largest cosmic-ray observatory in the world.

The active galactic nuclei seemed to originate from nearby galaxies that have huge nuclei in their middles, indicating black holes.

Scientists have theorized active galactic nuclei are powered by supermassive black holes devouring large amounts of matter.

Black holes swallow gas, light, dust and other matter from their host galaxies, and spew out particles and energy.

The finding that the particles emanated from galaxies known to have black holes adds robustness to the theory.

Brack, co-author of the paper on the discovery that appeared in the Nov. 9 edition of the journal Science, is a researcher in the University of Colorado physics department and also is a research affiliate at Colorado State University.

"This is a major, major result," said physics professor Uriel Nauenberg, a senior member of CU's High Energy Physics Group, who was not involved in the study. "It solves one of the mysteries of the source of cosmic rays that has been with us for 80 years."

Nauenberg said the discovery "heightens the chances" that a proposed sister facility of the Pierre Auger Observatory will be built in the Northern Hemisphere near Lamar in the coming years.

Colorado School of Mines scientists also played key roles in collecting the cosmic ray information at the observatory.

"The discovery is exciting and fundamental," Mines physics professor Lawrence Wiencke said.

The Pierre Auger Observatory in Lamar would be the largest detector array in the world, said Fred Sarazin, assistant professor at Mines, who heads the Colorado Coalition for Cosmic Ray Research. "Strong support from the state will be essential" to secure federal and international funding.

An international consortium of scientists meeting in Paris in June 2005 unanimously chose the region surrounding Lamar as the proposed Northern Hemisphere site for the estimated 4,000- to 6,000-square-mile Pierre Auger Observatory.

Giant tubs of water, 12 feet in diameter, would be set up along the country roads between Springfield and Lamar to capture the rare event when a super high-energy particle breaks through the atmosphere and leaves its footprint.

The vats of water would be placed about a mile apart in southeastern Colorado, where the farm roads generally are a mile apart.

Already, farmers and landowners have agreed to most of the spots where scientists want the water containers to be.

The cost of the observatory, which could be nearly $100 million, remains a roadblock, but scientists had put the chances of it getting built at better than 50-50.