Diamonddavej writes "The New York Times reports that the respected astrophysicist, James A. Van Allen, died yesterday at the age of 91. Apparently the fellow regularly worked at his office/laboratory up until a month ago. Prof. Van Allen team designed the Geiger counter that flew aboard Americas first orbiting satellite, Explorer 1. It detected unexpectedly intense levels of radiation caused by energetic particles trapped in the Earth magnetic field, the magnetosphere. The belts of radiation were mapped and characterised by later missions and were named the Van Allen belts in honour of their discoverer."