There’s another storm coming. For better or for worse, it won’t be delivering more wind, rain, flooding or even fire, as it instead pelted us with various forms of radiation, and possibly a good blast of ionic particles moving at over a million miles an hour as well. Like other big storms, the full extent of the event will be better understood once things have returned to normal, but in the mean time, NASA is keeping a close eye on the Sun where this particular blast of activity originated.
The specific disruption that was detected by the Solar Dynamics Observatory was a pair of solar flares, early in the morning of September 6. Flares are the result of warping magnetic fields in the Sun that build up over time, then suddenly release a glut of potential energy. The resulting burst heats surrounding solar material by millions of degrees, and sends out a wave of radiation, from large x-rays to tiny, fast gamma rays. Flares are categorized by their size and intensity as either a C-, M-, or X-class, depending on the intensity of emitted x-rays. This morning’s events were certainly heavyweights, with the first flare being measured as an X2.2 and the second an X9.3, the most intense explosion recorded in our solar system since 1997.
The fallout from these explosions was noticeable, but brief. Some of the energy from a flare can reach the Earth at the speed of light, arriving eight minutes after the magnetic field collapses on the Sun. Most of this radiation likely intercepted by our atmosphere before it could hit us, but that’s not easy on many of the technologies we rely on. Disruptions to the ionosphere can interrupt radio and GPS signals, and a one-hour blackout of radio and navigation signals was noted around 8:02 am EST this morning.
The corona as a plasma cannon
The bigger question at this point isn’t about the flares, but the chance that a coronal mass ejection (CME) took place at the same time. Confirmation is still needed, but the second flare possibly coincided with a blast of plasma, or magnetized particles similar to a super-heated gas, being sent towards Earth. Those particles may arrive at our doorstep in the next few days, and can trigger a bit more than some fuzzed GPS signals.
When CMEs come into contact with Earth’s own magnetic field, the collisions of charged particles and give off lights that we know as auroras, or Northern and Southern Lights. They can also interact with a wider variety of electronic devices, causing interference in radio signals, skewing GPS readings, and even overloading sensitive equipment. In 1989, the geomagnetic storm from a CME even caused blackouts in Canada. Even if this morning’s flares did include a CME, utilities can prepare for potential problems, minimizing the effects of a geomagnetic storm over the next few days.
The storm before the calm?
Like other weather patterns, there is a seasonal aspect to flares and CMEs. The Sun is actually moving towards the lower-intensity portion of it’s 11-year-cycle, promising a bit less activity in the near future. Of course, this morning’s activity included the most intense flare of the current cycle, so there’s no promise that the “off season” will necessarily be completely quiet.
Source: Two Significant Solar Flares Imaged by NASA's SDO by Karen C. Fox, NASA News