Uploaded on Nov 8, 2011
The black and white images show the magnetic field - the field is pointing toward us where it is white. The leading spots all have an intense negative polarity and the following spots are mostly positive.
The two polarities are pretty well separated and fairly stable, which is
why this region hasn't produced even more dramatic activity. The biggest
explosions happen when complex magnetic regions annihilate each other.
The glittering moving features around the spots follow the crests of magnetic waves. Not much new flux is emerging into this mature region, but there is a lot going on in the vicinity - and just about everywhere else too if you look carefully. The surrounding filamentary structures are weaker field regions that appear bright in intensity.
The movie with the granular yellow background shows the Sun's surface
brightness. Sunspot group 11339 is already large when it rotates around
to the front side of the Sun. The umbra is the darker, cooler part where the magnetic field is very strong and vertical. The surrounding orange
penumbra appears very dynamic because waves in the weaker horizontal magnetic field make it look like material is flowing out of the spot.
Watch how the darkest regions develop in time. The largest spot is more than five times the size of our Earth. What you cannot tell from these
pictures is which direction the magnetic field is pointing.
Credit: NASA SDO