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.