Word: sun
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Dates: during 1990-1999
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Neutrinos are the phantoms of the subatomic world. They seem to have no mass, may travel at the speed of light and are virtually impossible to detect. According to the standard theories of physics, these exotic particles are produced by various nuclear reactions. Quadrillions of neutrinos from the sun bombard the earth every second, yet most of them pass right through the planet without causing so much as a ripple...
Since 1968 scientists have been monitoring huge detectors for signs of these fleeting visitors from the sun. But so far, the results have been both disappointing and intriguing: the experiments have detected far fewer neutrinos than solar models predicted. Scientists were especially baffled by a recent report from a Soviet-American research team that set up a detector to monitor neutrinos emitted by the fusion of hydrogen atoms, the sun's main reaction. After four months of operation near the Soviet town of Baksan, the experiment has yet to turn up a single solar neutrino...
...case of the missing solar neutrinos has stirred growing excitement in the physics world. There are three possibilities: the Baksan experiment is wildly wrong, scientists don't understand the sun as well as they thought they did, or scientists have underestimated the elusiveness of the neutrino. The answer to the mystery could have profound implications for physicists' understanding of the universe. Two eminent theorists, John Bahcall of the Institute for Advanced Study in Princeton, N.J., and Cornell University's Hans Bethe have co-authored a paper that elaborates on an intriguing solution to the puzzle: neutrinos escape detection by changing...
Experimental evidence indicates that neutrinos come in three varieties: the electron neutrino, the muon neutrino and the tau neutrino. Solar fusion gives off the electron type. Bahcall and Bethe speculate that electron neutrinos change into the muon or tau versions somewhere between the sun and Earth. "It's as if they started out sweet," marvels Bethe, who won the Nobel Prize in 1967 for explaining how nuclear fusion powers the sun, "and then suddenly turned salty." Thus the Baksan experiment may have come up empty- handed because it was not designed to detect muon or tau neutrinos...
Back in the days when the economy was expanding, the cold war ending and the peace dividend looming large, Ronald Reagan cherished a famous fantasy about flying with Mikhail Gorbachev over the sun-soaked swatches of Southern California, with its mosaic of turquoise swimming pools and tidy lawns and fat white garages plump with new cars. "Those are the homes of American workers," he would proudly declare, describing a Hollywood dreamland where auto mechanics have summer houses and anyone can go to college...