Earth is surrounded by giant donut-shaped swaths of magnetically trapped, highly energetic charged particles. These radiation belts were discovered in 1958 by the United States' first satellite, Explorer 1. The discovery was led by James Van Allen at the University of Iowa, which eventually caused
The shape of the Van Allen belts can vary widely depending on how energetic the individual electrons are, and general conditions in the Earth’s magnetic environment. During geomagnetic storms (4), all three regions in the belts can balloon.