This week’s massive solar flare was “heard” by a NASA spacecraft in deep space and University of Iowa scientists have converted the signal into a sound humans can hear. The flare on the sun hurled off electrons at a very high speed, traveling 809-million miles in 69 minutes, where the Casini spacecraft picked up the phenomenon. U-of-I physics professor Don Gurnett helped build Casini and says the electrons produce a radio signal that decreases in frequency as they emerge, producing the odd whistling tone. He says the signals were traveling about the same as the speed of light, at roughly 186-thousand miles per second. Since people can’t hear radio signals at 1016-megahertz, the frequencies were shifted down into the audible range. The sound was also compressed from about four hours into about 20 seconds, as he says, “you wouldn’t want to sit and listen to this for four hours.” Casini is headed for Saturn and should arrive by July. It’ll be used to study the planet’s moons and rings. (Click on the link below for an audio version of this story)