Geomagnetic Storms   Energetic electromagnetic bombardments can also disrupt power grids and radio transmissions on earth, often producing power surges and static on the radio. Satellites can be disabled or even brought down. Why? Star wars for satellites Since most satellites are outside of the protection of the earth's atmosphere, they are the first to get hit by the severe geomagnetic storms that can result from sunspot activity. According to Dearborn, "As the accelerated energetic gas particles from the sun interact with the magnetic field that the earth has, and as they slide around the earth they form current sheets that satellites have to deal with. Satellites move from a region of space that has one charge to an area that has another charge, and when they cross those boundaries, the surface of the satellite can suddenly change polarity as it moves into a region where there is a different electric field. You get arcing and you get electric currents flowing inside the satellite in places where they're not supposed to flow, and that can be very bad for the satellites."   David Dearborn discusses how geomagnetic storms on the sun affect the earth. A real drag In addition to these changes from negatively charged to positively charged states (polarity), which can damage sensitive electronics, the increased solar emission also causes the earth's atmosphere to "puff out." According to Fisher, this creates increased drag on orbiting satellites. This increased drag can cause satellites to fall in from their orbits more rapidly than predicted. The 100+ ton Skylab station is a good example. Launched in 1973, the station was supposed to remain in orbit until the 1980s. The purpose of Skylab was, among other things, to study the sun. Ironically, due to increased solar activity, Skylab re-entered earth's atmosphere in 1979-- raining debris over the Indian Ocean and parts of Western Australia. High-energy particles get through Some of the high-speed charged particles from the Sun penetrate the earth's magnetosphere, where they can create waves of magnetic energy. This can interfere with both the flow of electric current in wires and the transmission of radio waves through the air. If the waves of energetic particles are strong enough, power grids can be overloaded, and radio signals drowned out. As Dearborn says, "The particles from the sun that get a little deeper into the earth's magnetic field can get trapped in the field ..., which produces the aurora that we can see and enjoy. But at the same time, they produce a lot of radio interference, especially at the lower radio frequencies, which can be so loud that you have difficulty broadcasting."   ©Copyright 2001 Regents of the University of California.