Yikes! Sun’s magnetic field set to flip

August 7, 2013 by  
Filed under Solar Energy Tips

In what NASA calls a major solar event, the sun’s magnetic field is soon going to flip. A complete shift in the polarity of the sun’s magnetic field occurs about every 11 years and now we are some three to four months away from another complete field reversal, according to Todd Hoeksema, director of Stanford University’s Wilcox Solar Observatory. This change will have ripple effects throughout the solar system, he said in a NASA news release.

Every 11 years or so, at the peak of each solar cycle, the sun’s inner magnetic dynamo re-organizes itself, causing its magnetic field to change polarity, NASA said. The last peak, or Solar Maximum, happened in 2000. The upcoming reversal comes at the midpoint of Solar Cycle 24, so half of the Solar Maximum is still to come. Although the magnetic field reversal is a major solar system event, its effect on Earth will most likely be limited to some stormy space weather around the planet, experts say.

Stanford’s Wilcox Solar Observatory is one of the few observatories that monitors the sun’s magnetic fields. Scientists there have been using magnetograms to track the sun’s polar magnetism since 1976 and have recorded three complete reversals, with the fourth soon to come.

“The sun’s polar magnetic fields weaken, go to zero, and then emerge again with opposite polarity. This is a regular part of the solar cycle,” said Phil Scherrer, a solar physicist at Stanford.

The effects of changes to the sun’s polarity extend to the very edge of the solar system where interstellar space begins. The heliosphere–the region of the sun’s magnetic influence–reaches billions of kilometers beyond Pluto, according to NASA. The heliosphere is organized around what solar physicists call the “current sheet,” a sprawling surface-bound electric current that is projected outward from the sun’s equator by the sun’s rotating magnetic field. It is approximately 6,213 miles (10,000 kilometers) thick and extends from the sun to beyond the orbit of Pluto.

When the field flips, the current sheet begins to undulate. Earth bobs in and out of the current sheet and these transitions can create stormy space weather, NASA said. However, a wavy current sheet offers increased protection against the high-energy particles known as cosmic rays, which emanate from deep space at speeds near the speed of light. Cosmic rays can pose a danger to astronauts and space probes and may affect Earth’s climate and weather systems.

Currently, data from the Wilcox Solar Observatory shows that the sun’s two hemispheres haven fallen out of sync The sun’s north pole has already reversed polarity, with the south pole lagging behind, according to Scherrer.

“Soon, however, both poles will be reversed and the second half of Solar Max will be underway,” Scherrer said.

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