Word: solarization
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Dates: during 1990-1999
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Already one of these new satellites, the Solar and Heliospheric Observatory, or SOHO, has taken movies of hot gas streaming into space from a magnetic belt girdling the sun. And the Polar Satellite, so-called because it passes over the North Pole, recently snapped the clearest pictures ever seen of the aurora borealis, the shimmering curtains of light that are the visible fallout from space storms...
What's most surprising, observes Joe Gurman, a space physicist at NASA Goddard Space Flight Center, is that all this is occurring despite the fact that we're currently in a solar minimum--the interval of relative calm that reigns between the end of one 11-year sunspot cycle and the beginning of another. Sunspots always signal more violent solar activity than average. But, says Gurman: "We now know that there's no such thing as a quiet...
What drives space weather is the solar wind, a never-ending gush of magnetized gas spewed out by the corona, the sun's glowing outer shell. This gas is so hot (two million degrees Fahrenheit) that atoms of hydrogen and helium are homogenized into a dilute plasma, composed mainly of negatively charged electrons and positively charged protons. Yet the solar wind is a gossamer thing, far less substantial than a whisper. "What you have," marvels Gurman, "is a million tons of matter moving at a million miles per hour. But its density is so low that essentially you're dealing...
...solar wind races toward the edges of the solar system, it smashes into the magnetosphere, a long, teardrop-shaped region of space that marks the boundaries of the earth's magnetic field. The magnetosphere protects the earth by deflecting most of the solar wind around the planet the way a windshield deflects air around a car. Still, untold trillions of charged particles manage to leak through. Some are trapped to form the Van Allen radiation belts that surround the earth. Others spiral down the magnetic field lines that project from the North and South poles. Energy unleashed by this disturbance...
...leakage is greatest during geomagnetic storms, which happen when the sun turbocharges the solar wind by spewing out giant blobs of plasma. Ejected at extremely high speeds, they push particles through the magnetosphere with an unusual amount of oomph. During solar minimum, the biggest blobs come from openings in the sun's magnetic field called coronal holes. "Gas spews out of these holes," explains University of Colorado space physicist Daniel Baker, "like water from a fire hose's nozzle." If the nozzle is aimed toward earth, the consequences can be dramatic. Plasma from coronal holes may well have triggered...