The magnetic field of the sun plays a huge role in our galaxy. It’s
12,000 times larger than Earth’s magnetic field, extending even beyond Pluto. It has two poles like a
bar magnet, and like most stars, the convection of plasma generates its magnetic field. Compared to the
magnetic fields of the other planets in our solar system, however, the sun’s magnetic activity is more extensive including solar flares, sunspots, space weather, and pole reversal.
Sunspots and Solar Flares
The
sun’s magnetism causes some interesting phenomena. Because the star is essentially fluid, the magnetic field lines are always shifting. The surface of the sun moves at different speeds depending on latitude causing the magnetic field to act like a rubber band. When you pull one end of a rubber band away while holding the other end down, it will snap back to its original position. As the surface of the sun moves, it pulls one section of the magnetic field lines away from the others at a faster pace. Eventually, the lines snap back into position, which causes sunspots and solar flares. The sunspots, when compared to Earth, are massive and occur within the 11-year solar cycle. The solar cycle also determines when the sun’s magnetic field flips.
Pole Reversal
The sun’s magnetic field reverses its polarity every 11 years, corresponding with the solar cycle of activity. While the switching of positive and negative charges on our most important star impacts the entire galaxy, we will notice next to nothing on Earth. The pole shift could cause disruption in electrical power grids or some space weather like a
geomagnetic storm but this is unlikely because the
solar cycle of the sun is the weakest it has been in the past 100 years.
We are currently in solar cycle 24.
Solar cycle 24 peaked when the north pole shifted in June 2012 and the south pole finished its shift in July 2013. In the image above you can see the magnetic pole reversal decrease in strength over the past few solar cycles. Scientists aren’t sure why the solar cycles and the magnetic poles of the sun are gradually 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. 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,”
Todd Hoeksema, a Stanford solar physicist, said of the solar cycle trend.
Look for the next magnetic pole shift of the sun in about nine years when solar cycle 25 peaks!
