Coronal holes on the farside of the Sun

For the past week, all eyes have been on the Earth-side of the sun, where sunspots 1158 and 1161-1162 have unleashed some of the strongest flares in years.

Meanwhile, the farside of the Sun has been busy, too.

Here is the movie from NASA's STEREO-B probe covering the first 20 hours of Feb. 19th. 

A huge active region is transiting the farside and crackling with flares; it will turn toward Earth in about a week.In this 3-D simulation of the rotating Sun, we can see a large coronal hole on the side of the Sun that is not facing Earth. Regions of coronal holes on the Sun can be 100 times less dense than surrounding material. For this reason, magnetic field lines in coronal holes allow dense streams of proton particles to propagate away from the Sun into surrounding space. We could be looking at some more energetic bursts of solar activity during this period when the Sun rotates.