Thursday, February 13, 1997
Japan May Add To Utah Projects On Cosmic Rays
THE SALT LAKE TRIBUNE Another gigantic science project -- a $60 million to $100 million set of cosmic-ray telescopes -- may be built in Utah by Japanese physicists who now are assembling prototypes at Dugway Proving Ground. Wednesday's revelation came only five months after an international science team picked Utah as the site of a different $50 million cosmic-ray observatory. ''How about a slogan? Utah: Cosmic-ray capital of the world,'' Gov. Mike Leavitt said after learning of the Japanese project. If Japan's government agrees to fund the Telescope Array project, it would cement Utah's position as the world leader for research aimed at understanding the mysterious, incredibly powerful source that hurls super-high-energy cosmic-ray particles toward Earth. A funding decision won't be made for a few years. But if the new project is built, Japanese researchers already decided ''it's clearly going to be in Utah,'' University of Utah physicist Pierre Sokolsky said during the U.'s Science at Breakfast lecture. He said the array of 100 cosmic-ray telescopes would be built either at Dugway, which is the site of the University of Utah's $13 million Fly's Eye cosmic-ray observatory, or in Millard County, which in September was chosen as the site for a $50 million cosmic-ray observatory named the Pierre Auger Project. The Telescope Array would be constructed by 2005 by the University of Tokyo, other Japanese universities and the University of Utah, although almost all the money would come from Japan, Sokolsky said. He said Japanese scientists decided to build their telescopes in Utah almost a year ago, but no public announcement was made. Plans have solidified since last summer, when the Japanese built three prototype cosmic-ray telescopes at Dugway, Sokolsky said. They will complete the $3 million pilot project by adding four more telescopes by this summer. U. physicist Paul Sommers said the Japanese telescope project ''is very uncertain still. . . . It's 50-50 if it will come to pass.'' Richard Koehn, the university's vice president for research, called the planned Japanese facility ''an extraordinarily significant step in the development of a world center of astrophysics and cosmic-ray study'' in Utah. Sokolsky said the Japanese Telescope Array would complement the Pierre Auger observatory and be more sensitive than the Fly's Eye. He said the U.S. and other governments now are considering requests for $50 million to build the Auger observatory in Millard County. A twin of that facility also will be built in Argentina. Cosmic rays from outer space constantly bombard Earth, and ''there is one of these cosmic-ray particles going through your head every second,'' Sokolsky said. The rays are subatomic particles, including electrons, protons and nuclei of the lighter elements. Many cosmic rays come from exploding stars within our own Milky Way galaxy. But scientists are perplexed by the source of super high-energy cosmic rays bombarding Earth at almost the speed of light -- particles Sokolsky called ''visitors from beyond our galaxy.'' The most energetic one ever detected was observed by the Fly's Eye in 1991. It had an energy of 300 billion billion electron volts. Sokolsky said that is roughly the same amount of energy in a fast-pitched baseball, but carried by a single subatomic particle. Possible sources include decaying cosmic strings, which are theorized defects in time and space left over from the birth of the universe; supermassive black holes, which are superdense clusters of billions of collapsed stars; and the mysterious ''dark matter'' scientists believe makes up 90 percent of the universe but still hasn't been identified. Koehn said existence of super-high-energy cosmic rays means either ''there are new laws of physics out there we don't know about, or the laws of physics we know have to be restructured somehow.'' There are several reasons Utah is becoming the global center of cosmic-ray research. They include the vast, flat undeveloped landscape and dark, unpolluted skies of the state's western desert, coupled with proximity to a major university and adequate roads and utilities. Another reason is Utah's history of pioneering cosmic-ray research. When a cosmic ray hits nitrogen gas in Earth's atmosphere, it causes a faint blue fluorescent flash. The collision also triggers a cascade of other particle collisions, called an air shower. Cosmic-ray researchers traditionally used devices that detected air-shower particles reaching the ground. But U. physicists George Cassiday, Eugene Loh and others pioneered the use of large mirrors aimed at the sky to detect the fluorescent flashes. Many scientists were skeptical of the method, but its effectiveness was proven at the Fly's Eye, which was built during 1981-82, Sokolsky said. The original $3 million Fly's Eye, which includes 54 sets of mirrors on two hills at Dugway, now is undergoing a $10 million upgrade to convert it into a more sensitive device named the High-Resolution Fly's Eye. The upgrade will be completed by 1999, Sokolsky said. Meanwhile, an international group led by Fermi National Accelerator Laboratory outside Chicago decided to build twin $50 million cosmic-ray observatories in Millard County and Argentina. They will be named for French physicist Pierre Auger, who discovered air showers in 1938. The Utah observatory, located south of Delta and west of Fillmore, will be completed in 2001 if the U.S. and other governments contribute the needed cash. Each Auger observatory will include 1,657 tanks of water spread across a 1,200-square-mile area. The tanks would detect cosmic-ray air-shower particles that reach the ground. Each Auger observatory also will include three sets of 5-foot-diameter mirrors to detect air-shower flashes in the sky. But those mirrors would detect no more than 15 percent of the incoming cosmic rays detected by the water tanks, Sokolsky said. Japan's Telescope Array would include 100 telescopes, each containing 19 mirrors with a total surface area almost three times larger than the upgraded Fly's Eye mirrors. That would make them more sensitive than the High-Resolution Fly's Eye and complement observations by the Utah Auger observatory, Sokolsky said. In 15 years of operation, the Fly's Eye detected only one super-high-energy cosmic ray. Sokolsky said High-Resolution Fly's Eye should observe six to 10 each year, while each Auger observatory and the Telescope Array should detect 60 to 100 annually. |
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