You’d think the return of blemishes on your face would be an unwelcome thing.
But if the face is that of the Sun, and the blemish is actually a planet-sized knot of tangled magnetic fields, then it’s actually most welcome indeed. Because now we’re starting to understand why they’re coming back.
After nearly two years of an acne-free surface, the first sunspots are starting to pop up on the Sun. Sunspots are regions on the Sun where the magnetic field lines of our nearest star erupt through its surface, and are an indicator of the amount of magnetic activity going on inside the Sun. Unlike a simple bar magnet, the solar magnetic field activity increases and decreases on a roughly 11-year cycle, and the number of sunspots follows in response. When the magnetic activity starts to rise after the cycle bottoms out, sunspots start to appear at a solar latitude of 22 degrees, and spread north and south from there.
Right now we’re at the bottom of the cycle, and sunspots are rare. But this two-year lack of spots has been the longest such period for nearly a century, and it’s had solar astronomers scratching their heads. That’s not too surprising, as the Sun is a fiendishly and vastly complex system of churning gas, and it’s numbingly difficult to observe and model it.
But astronomers have just made an important breakthrough in solar observations that links the way the gas under the Sun’s surface behaves with the way sunspots form. This is very cool and exciting news!