The sun is close to a big change in which its magnetic field will flip, but this happens about once every 11 years, according to a NASA news release.
The sun's magnetic polarity flips at the peak of each solar cycle as its inner magnetic dynamo re-centers itself.
"It looks like we're no more than 3 to 4 months away from a complete field reversal," says solar physicist Todd Hoeksema of Stanford University. "This change will have ripple effects throughout the solar system."
Stanford's Wilcox Solar Observatory (WSO), of which Hoeksema is the director, is one of the few telescopes that monitor the sun's polar activity. In the same way that Earth scientists study the planet's polar change for its effects on the climate, so do solar physicists for the sun.
Scientists have been watching the sun's polar magnetism since 1976 and have tracked three reversals since and the fourth is on the way.
"The sun's polar magnetic fields weaken, go to zero, and then emerge again with the opposite polarity," Stanford solar physicist Phil Scherrer said. "This is a regular part of the solar cycle."
The event is, quite literally, a huge one. When the sun's magnetic field flips, the ripples can be felt all the way to the brink of the solar system. The "current sheet" is a stretched surface protruding from the sun's equator where the magnetic field creates an electrical current. The current is a mere one ten-billionth of an amp per square meter, but it flows through an area 10,000 km thick and billions of kilometers wide. The sun's heliosphere is centered around this one sheet.
"The sun's north pole has already changed sign, while the south pole is racing to catch up," says Scherrer. "Soon, however, both poles will be reversed, and the second half of Solar Max will be underway."
