For 40 years engineers and physicists have puzzled over "the hiss," a mysterious electromagnetic wave surrounding the earth that, when played through a loudspeaker, sounds like the hissing and swishing between tracks on a scratchy vinyl record. In March UCLA physicists reported that the hiss may start its existence as a wave called "the chorus," which has long been seen as entirely unrelated to the hiss. The effects of the hiss and the chorus are well known to NASA scientists. The hiss occurs throughout the plas-masphere (the zone thousands of miles above the earth that teems with ionized gases), removing the plasmasphere's high-energy electrons and tempering their lethal power. Thousands of miles beyond the hiss, outside the plasma-sphere, is a vastly different kind of electromagnetic wave, the chorus. Through a speaker the chorus sounds like a choir of birds chirping and whooping in a rookery.
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