Artist's depiction with cutaway section of the two giant donuts of radiation, called the Van Allen Belts, that surround Earth.
An artist’s depiction with cutaway section of the two giant donuts of radiation, called the Van Allen Belts, that surround Earth. A NASA-funded balloon campaign in Antarctica launched in December 2012 and December 2013 is studying what causes bursts of particles to precipitate out of the belts down to Earth. Credit: NASA/Goddard Space Flight Center/Scientific Visualization Studio