Sun Flipping Out, Magnetically Speaking
“The sun’s polar magnetic fields weaken, go to zero, and then emerge again with the opposite polarity,” said Phil Scherrer, a solar physicist at Stanford University, in a statement from NASA. “This is a regular part of the solar cycle.”
What can we expect from this? Not much, scientists say. It’s the fourth time the sun’s magnetosphere has done this since observations of the sun’s 11-year cycle began in 1976. This marks the midpoint of Solar Cycle 24, NASA said.
“The sun’s north pole has already changed sign, while the south pole is racing to catch up,” said Scherrer in the statement. “Soon, however, both poles will be reversed, and the second half of Solar Max will be underway.”
Spacially speaking, it is a “big event,” as NASA noted. This is the heliosphere we’re talking about, the magnetic field that the Voyager probe is in the process of penetrating on its way out of the solar system.
“Changes to the field’s polarity ripple all the way out to the Voyager probes, on the doorstep of interstellar space,” NASA says.
But here on Earth the effects will be negligible and potentially beneficial,National Geographicsaid. The “current sheet,” the solar-system-wide, 10,000-kilometer-thick plane of current that stretches out from the sun’s equator past Pluto, becomes wavy during the switch, which makes it a better protection against harmful cosmic rays, according to Space.com.
The sun has been at the high point of its cycle this year, with activity expected to peak in 2014 or so. The heightened activity could cause solar storms feisty enough to take out chunks of the electrical grid across the planet.
But the current cycle is not nearly as volatile as in the past, say sun-monitoring scientists. Wilcox Solar Observatory at Stanford University is one of the few facilities in the world that monitor the sun’s polar magnetic fields. Since that first set of observations, the sun’s polar fields have been weakening.
“The polar fields have been getting weaker and weaker over the last 30 years, and so also the following sunspot cycles have been getting weaker over the years,” said Wilcox Observatory director Todd Hoeksema in NASA’s statement. “We don’t really understand why, or even if that’s the cause or if they’re both symptoms of the same thing. It’s a fun and interesting puzzle.”