Slate – by Phil Plait, October 22, 2014
Sure enough, as predicted, the freakishly huge sunspot AR 2192 blew out a powerful X-class flare [last Wednesday] around 14:00 UTC. The picture above shows the view from the Solar Dynamics Observatory; in the far ultraviolet it’s very sensitive to solar activity. Note the Earth for scale there, in case you need the Universe to crush your feeling of self-importance under its heel.
Flares are massive explosions on the Sun associated with sunspots. You can read about them in detail in an earlier post I wrote, but the quickie version is that magnetic fields in sunspots can store vast amounts of energy. Looping magnetic field lines can get tangled up and snap, releasing their energy as mind-crushing explosions called flares.They’re rated by how much X-ray energy they emit; for example M-class are “moderate”, and X-class are the highest.