• January 1, 2009

    Episode 198: Cosmic Ray Invasion

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    A series of balloon flights over Antarctica was designed to count up the kinds of cosmic rays that shower through the solar system from distant regions of the galaxy. These cosmic rays are usually produced by violent events such as supernovae explosions. The Advanced Thin Ionization Calorimeter (ATIC) detectors did indeed find lots of high energy particles, but many more high energy electrons than expected. This is curious because it is hard for the electrons to travel over large distances -- they usually hit something along the way. So they must have come from nearby. But from what?