Using NASA’s Van Allen Probes, new research reveals that the Van Allen radiation belts contain a nearly impenetrable barrier that prevents the fastest, most energetic electrons from reaching Earth.The Van Allen belts are a collection of charged particles, gathered in place by Earth’s magnetic field. They can wax and wane in response to incoming energy from the sun, sometimes swelling up enough to expose satellites in low-Earth orbit to damaging radiation. The discovery of the drain that acts as a barrier within the belts was made using NASA’s Van Allen Probes, launched in August 2012 to study the region. A...