Solar scientists track solar cycles by counting sunspots. Sunspots are caused by magnetic activity that inhibits convection regions forming “colder” areas (roughly 3,000-4,500 K) on Sun’s photosphere. They appear dark only in contrast to the surrounding area (at about 5,780 K). As the Sun’s magnetic field changes over time (back and forth from a maximum to a minimum), the number of sunspots varies. The current solar cycle (24), “officially” began with the appearance of sunspot 981 on January 4, 2008. For almost two years the cycle 24 has been quite boring (the sun has been spotless for about 260 days this year). As the expected increase of solar magnetic activity is about a year overdue, the last week’s appearance of sunspot 1034 and the active sunspot region 1035 (which grew into size of several Earth radii) finally “brightened” things a little.
In the video above, the Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric Observatory (SOHO) captures the appearance of the sunspot region 1035 on December 14, 2009.