Number 463 (Story #1), December 22, 1999 by Phillip F. Schewe and Ben Stein|
THE SOLAR WIND DISAPPEARED for a day back on May 10/11, allowing Earth's magnetosphere to balloon out to the orbit of the Moon. Ironically, the greatly lowered solar wind flux of particles and solar magnetic field allowed high-energy electrons from the sun's corona to penetrate directly to our upper atmosphere unadulterate, where the electrons' characteristic x-ray emissions were observed by satellites over the North Pole for the first time. Such a "polar rain" had been predicted years before. Normally the coronal electrons (with energies of tens of keV, corresponding to temperatures of millions of degrees) lose much of their energy through scatterings with other particles on their ride from sun to Earth and in the topsy-turvy trajectories experienced at our magnetosphere. At last week's meeting of the American Geophysical Union in San Francisco, these results were reported by a number of speakers, including David Chenette of Lockheed, Jack Scudder of the University of Iowa, and Keith Ogilvie of NASA Goddard. (Images available at www-spof.gsfc.nasa.gov/istp/news/9912).