SPACE PHYSICS:
Seeking a Source of Potent Cosmic Rays
David Ehrenstein
COLLEGE PARK, MARYLAND--Every so often, Earth's outer atmosphere is blasted by subatomic particles packing so much energy that they defy explanation. No known source in our cosmic neighborhood has enough power to generate them, yet if they traveled far, they would lose energy to the ubiquitous microwave background radiation. Moreover, ground-based detectors built to monitor a wide spectrum of cosmic rays have spotted only a handful of these superenergetic particles, known as UHECRs. But physicists are planning ways to collect a lot more information on them. At a NASA-organized conference here at the University of Maryland last month, researchers backed a proposal to fly twin satellites to keep watch for the flashes of light generated when energetic particles, including UHECRs, slam into the atmosphere, creating showers of secondary particles.
