Van Allen radiation belt, doughnut-shaped zones of highly energetic charged particles trapped at high altitudes in the magnetic field of Earth. The zones were named for James A. Van Allen, the American physicist who discovered them in 1958, using data transmitted by the U.S. Explorer satellite.
Van Allen’s experiment on Explorer 1, which launched Jan. 31, 1958, had a simple cosmic ray experiment consisting of a Geiger counter (a device that detects radiation) and a tape recorder. Follow-up experiments on three other missions in 1958 — Explorer 3, Explorer 4 and Pioneer 3 — established that there were two belts of radiation circling the Earth.
While observations have continued for decades, our knowledge of the belts became more enhanced when the Van Allen Probes launched in 2012. They found that the belts were more complex than previously imagined. The probes showed that the shape of the belts depends on what particle is being studied. They also uncovered information hinting there is less radiation than imagined in certain parts of the Van Allen belts, which means spacecraft and humans would not need as much radiation protection if they are voyaging in that region.
Picture Credit : Google