PALO ALTO, Calif., Aug. 7 (UPI) -- Scientists say U.S. observatories are providing evidence something big is about to happen on the sun -- a complete reversal of its magnetic field.
"It looks like we're no more than three to four months away from a complete field reversal," solar physicist Todd Hoeksema of Stanford University said in a release from NASA. "This change will have ripple effects throughout the solar system."
The sun's magnetic field changes its North-South polarity about every 11 years at the peak of each solar cycle as the sun's inner magnetic dynamo re-organizes itself, scientists said.
The imminent reversal will mark the midpoint of Solar Cycle 24, as half of the solar max" will be behind us with half yet to come, they said.
Stanford's Wilcox Solar Observatory, headed by Hoeksema, is one of the few observatories in the world that monitors the sun's polar magnetic fields.
Instruments at the observatory have been tracking the sun's polar magnetism since 1976, and have recorded three reversals in that time -- soon to be four.
"The sun's polar magnetic fields weaken, go to zero and then emerge again with the opposite polarity," Staford solar physicist Pill Scherrer explained. "This is a regular part of the solar cycle."
This time, however, the sun's two hemispheres are temporarily out of sync, he said.
"The sun's north pole has already changed sign, while the south pole is racing to catch up," Scherrer said. "Soon, however, both poles will be reversed, and the second half of solar max will be underway."
