Surprise In Earth's Upper Atmosphere

The sun, in addition to emitting radiation, emits a stream of ionized particles called the solar wind that affects the Earth and other planets in the solar system. The solar wind, which carries the particles from the sun's magnetic field, known as the interplanetary magnetic field, takes about three or four days to reach the Earth. When the charged electrical particles approach the Earth, they carve out a highly magnetized region — the magnetosphere — which surrounds and protects the Earth.Charged particles carry currents, which cause significant modifications in the Earth's magnetosphere. This region is where communications spacecraft operate and where the energy releases in space known as substorms wreak havoc on satellites, power grids and communications systems.The rate at which the solar wind transfers energy to the magnetosphere can vary widely, but what determines the rate of energy transfer is unclear.The energy of the particles and the fields in the magnetosphere can vary by large amounts. It can be 10 times higher or 10 times lower from day to day, even from half-hour to half-hour.The magnetosphere was discovered in 1957. By the late 1960s, it had become accepted among scientists that the energy transfer rate was controlled predominantly by the interplanetary magnetic field.