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| Vol. 17, No. 6 | Oct. 9, 1997 |
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| Vol. 17, No. 6 | Oct. 9, 1997 |
Cosmic rays, those supercharged projectiles flung into space by solar disturbances and dying stars, may contain clues to the chemical origins of galaxies. These speedy particles also interact with the sun's magnetic wind, which zaps electrical power grids on Earth, damages communications satellites and may pose a health hazard for astronauts.
Unlocking the secrets of cosmic rays-and predicting disturbances caused by solar wind-may soon prove easier for scientists with the Bartol Research Institute at UD, thanks to a $1.2 million National Science Foundation (NSF) grant. Along with $705,400 worth of equipment donated to Bartol by the Canadian government, the NSF grant will support four new cosmic-ray monitoring stations, to be established throughout northern Canada.
The facilities are planned as part of Spaceship Earth, an NSF effort to predict bad space weather by monitoring cosmic rays from nine ground-based stations in Canada, Russia and Antarctica, said Bartol's John W. Bieber and Paul Evenson. Researchers at each station will track neutrons, one of the fundamental constituents of all matter, using instruments two times larger than an existing detector on the roof of Sharp Laboratory.
"We will essentially be taking a picture of the solar wind around the Earth by examining how the paths of cosmic rays are disturbed by magnetic and electric fields in the wind," explained Bieber, lead investigator for the project.
Cosmic rays travel almost as fast as light-roughly 1,000 times faster than solar wind particles. The Bartol researchers said they think cosmic rays may, therefore, provide advance warning of potentially disruptive solar wind activity. "Cosmic rays reach Earth much, much faster than solar wind, and they interact with wind particles," Bieber said. "If we knew more about this relationship, we might be able to avoid electrical blackouts and communication problems based on our readings of cosmic rays."
Bieber, Evenson and their Bartol colleagues will focus primarily on cosmic rays resulting from massive explosions on the sun's surface, known as solar flares, and coronal mass ejections, the clumps of magnetized solar matter periodically flung into space by the sun. The sun's magnetic activity intensifies and wanes based on a 22-year cycle, which will reach its peak again in the year 2000, Evenson noted.
"These solar wind particles clearly can cause serious and costly damage," Evenson said. "Solar wind was believed to cause a major power failure in Canada in 1989, and it may have played a role in more recent damage to an AT&T satellite. A warning system might help us prevent losses by protecting vulnerable systems before solar wind disturbances strike."
A system for predicting space weather also would be useful to people on high-flying aircraft such as the Concorde and astronauts onboard Mir and the planned international space station. The Spaceship Earth project will rely on nine cosmic-ray monitoring stations located in a ring around the globe's northernmost regions. Canadian stations are planned from Inuvik, on the nation's northwestern tip; to Fort Smith, in the midst of the country; Winisk on the southern edge of the Hudson Bay; and Nain on the northeastern coast.
"It's a circle of eight stations at extreme northern latitudes, plus one in Antarctica," Bieber said. "Equipment in each station will let us look at cosmic rays having an impact on the Earth's equatorial plane from nine different directions."
For the past 60 years, Bartol scientists have been studying the origin and nature of cosmic rays using high-altitude balloons launched from Lynn Lake in Canada, as well as data from spacecraft orbiting the Earth.
Bartol's participation in the Spaceship Earth project will expand the institute's existing network of neutron detectors in Delaware, Antarctica, Greenland and Canada.
-Ginger Pinholster
Photo by Jack Buxbaum
