The sun is spoiling us for superlatives. Last night, giant sunspot AR 2192 – the largest sunspot astronomers have observed in nearly 25 years – erupted in an X3.1-class solar flare, the most powerful of four flares to burst from the region since October 19th.


The shot you see above was captured by Sergio Castillo of Corona, California, who was monitoring the sunspot with his backyard telescope when it erupted. "This flare was so intense that it almost shorted out my computer! Well ... not really," Castillo told, "but I knew right away that it was an X-class eruption." Here's a wider view of the flare, as seen by NASA's Solar Dynamics Observatory:

AR 2192 is truly enormous. While it's been called a "decade-class" phenomena, AR 2192 is actually the largest sunspot astronomers have observed in close to a quarter century. According to Alex Young, a solar astrophysicist with NASA's Goddard Space Flight Center, the last time a sunspot this huge lugged its way across the sun's surface was November of 1990. As images of this week's partial solar eclipse have begun to roll in, AR 2192 has been clearly visible in many of the photographs, as well it should be; the highly active solar region is about as wide as Jupiter. For a sense of scale, see this comparison image created by Young. You practically have to squint to see Earth:

As we've seen this week, AR 2192 is not only gigantic, it's also highly active. Since October 19th, the sunspot has fired off four solar flares. Three of those have been X flares, the strongest class of solar flare there is: An X1.1 on Sunday, an X1.6 on Tuesday, and last night's flare, a tremendous X3.1-class burst. Bear in mind that an X3 is a twice the strength of an X2, which in turn is twice the intensity of an X1. When directed at Earth, X-class flares can lead to planet-wide radio blackouts and radiation storms. They are major solar events.


Fortunately, AR 2192's latest flare does not appear to have directed much of its wrath in our direction, but we'll be keeping an eye on NOAA's space weather prediction center, just in case.