M9 Solar Flare of January 23 2012; credit: Solar Dynamics Observatory

Let's see, what's the weather like right now (sticks finger into the air). Speed, 1.2 million miles per hour, density 1.1 protons per cubic centimeter, temperature 200,000 degrees Celsius. Sound a bit extreme? Surely climate change hasn't made things THAT batty. As a matter of fact, conditions have calmed down in the last several hours.

Okay, I'm not talking Earth weather—if I were, we'd all be dead, fast. I'm talking space weather, and a subsidence in its condition following a powerful solar flare whose ejecta struck Earth on Tuesday, causing a strong geomagnetic storm, and some pretty Northern and Southern Lights.

The flare in question, associated with the big sunspot numbered 1402, erupted on January 23rd, launching a coronal mass ejection–a "cantaloupe" of plasma that makes Earth look like a grape. Rated as an M9-class flare, it packed umph just shy of what's necessary for adult "X-class" flaredom, the most power kind.

When it reached us the megablob of plasma struck Earth's magnetic field, causing the geomagnetic storm and a minor list of annoyances (communications interference, for the most part, and some reported concern to an electrical grid operator). On the showier side of solar activity, the storm generated spectacular auroras in high latitudes.

The Sun's magnetic activity—the source of disturbances like flares and oft-associated coronal mass ejections—has been on the rise for the last couple of years, heading for a forecasted peak in activity ("Solar Maximum") in 2013. We're in "storm season," with respect to the Sun's 11-year magnetic activity cycle, so we can expect more, and stronger, flares and geomagnetic storms in the next year or two to come.

Back when I was growing up (1960's) I learned that space is a vacuum, void of the gases we find in Earth's atmosphere. It was a stark picture of emptiness, at least as this child comprehended the data. Sure, sunlight and starlight streams through that vacuum, but other than that, Dr. Science explained, if I took one space-step outside of my personal Mercury space capsule without protection, I'd suffocate and my blood would boil and freeze at the same time—not to mention that I'd get cooked by the dangerous ultraviolet and X-ray radiation shining from the Sun.

Okay, close the Time-Life science series book entitled "Space" and open an astrophysics textbook of my 1960's youth era, and I would have learned that there's more to the vacuum of space than nothing.

Our Sun, a gargantuan fusion bomb that consumes a mass of hydrogen comparable to that of the entire human race each second, continually spews more than just sunlight into the space around it. Hot, electrically charged gas (plasma), mostly hydrogen nuclei and electrons, blended with an accompaniment of magnetic fields, blow outward from the Sun's surface and atmosphere all the time.

That's the solar wind, and its conditions, whether normal or stormy, is what makes space weather. So when you're curious about the weather conditions in the space surrounding Earth and its protective magnetic field, poke your finger skyward and extend your arm—oh—about 50,000 miles…or just go to a space weather website like Spaceweather.com.

Magnetic activity on March 27th; white indicates N
magnetic poles, black S. Credit: ESA/SOHO/NASA.

A few blogs back I wrote about the 11-year cycle of ups and downs in solar activity–the Solar Cycle –and how over the last year or so the baton was supposedly passed from Cycle 23 to Cycle 24. But there has been an occurrence on the Sun that suggests we may be in somewhat of a gray zone….

For the past two or three years, the Sun has been downright boring. We set up our Sunspotter telescopes for visitors and try very hard to make what we see seem interesting–"See that perfectly blank circle of light? That’s the Sun! Really it is!"

About a week ago, the tedium was suddenly broken by a train of sunspots that rotated into view on Sun’s disk. Five–count'em– five sunspots! Finally, something to actually look at! And in the eyepiece of our Coronado Hydrogen-Alpha filter telescope there were filaments and plage! What are filaments and plage? Exactly! People wanted to know….

Then came the weird part: these were not Cycle 24 sunspots (I am not the Dread Pirate Roberts…); they were refugees from the supposedly defunct Cycle 23. While the distinction may be a fine point that doesn’t worry most of our visitors, it can still be a good talking point.

So, why were these five sunspots fingered as old solar trekkers rather than members of the next generation? It all comes back to what a solar cycle is–and sunspots, flares, prominences, and plage are merely details: manifestations of the Sun's magnetic convulsions. The Sun, like the Earth, generates an enveloping magnetic field–a big donut with a north and a south magnetic pole. On smaller scales there are plenty of twists and swirls and knots in the field caused by local "hot spots" of magnetic activity–which are what produce features like sunspots in the first place.

At solar maximum–the peak of activity of a solar cycle–the Sun's magnetic poles flip over, or reverse. In fact, it's this reversal that really lets us know when a solar maximum has arrived. (Earth's magnetic field also reverses polarity periodically–although this only happens every 200,000 years, on average.)

At the beginning of a solar cycle, new sunspot activity can be found at high solar latitudes, and as the cycle progresses, activity migrates toward the equator. On a finer nuance, the magnetic polarity of sunspots–which can be N or S, and are usually paired up, like the two ends of a bar magnet –are typically oriented east-to-west on the Sun's surface, one leading to the other as the Sun rotates. Which type of pole (N or S) leads and which trails depends on the overall magnetic "flip" state of the Sun's magnetic field.

To round out this report, the five surprise sunspots of yesterweek were lined up close to the Sun's equator, and the orientation of their magnetic poles bespoke their affiliation with the outgoing magnetic administration (Cycle 23). So far, only a single, high-latitude, reverse-polarity sunspot observed last January has signaled Cycle 24 .

Who knows? Maybe the magnetic candidates of Cycle 24 are still holding primaries, caucuses, and debates and have yet to begin some serious campaigning…

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

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