This photo, taken by the Cassini spacecraft in 2000 as it flew by Jupiter on its way to Saturn, reveals Jupiter's magnetosphere. Jupiter has the system's strongest magnetic field, which surrounds the planet and helps creates the magnetosphere. A magnetosphere is formed when a stream of charged particles from the sun (the solar wind) is deflected by the planet's magnetic field — in this case wrapping around the planet like a giant teardrop. As NASA describes it, a "magnetosphere is a bubble of charged particles trapped within the magnetic environment of the planet." This particular bubble stretches across 1.8 million miles of space.