Merging Sunspots 
One core area of Sunspot 1117 emerged, and then edged over and merged with another core area over three days (Oct. 25-27, 2010) to form a much larger, active sunspot region. Portions of sunspot groups can shift over time. Each dark umbra (darkest area) in the October 26 snapshot from the HMI instrument on SDO is as wide as Earth (the daily movie for October 26 is at http://sdo.gsfc.nasa.gov/assets/img/dailymov/2010/10/26/20101026_1024_HMII.mpg). The magnetic field of this area has been creating a number of small (B- and C-class) solar flares, though no large flares have erupted there to date. Sunspots are cooler, darker areas on the Sun's surface where energy and light are suppressed by intense magnetic forces.
Search Tag(s): sunspots, intensitygram
Movies
- spotchangeFD_1024.mov - mov
- spotchange_zm_best1.mov - mov
- spotchange_zm_lo.mov - mov
- spotchange_sq.mpg - mpeg