January 16, 2013
NASA SDO – Tracking AR1654 (Jan 7 – 15, 2013)
Active Region 1654 has traveled half across the Earth facing side of the Sun. This video tracks this region starting January 7 through January 15, 2013.
Despite its big size, over 120,000 miles from end to end on January 12, this active region has only produced a couple of medium sized solar flares (M-class flares). However, it is a beautiful view to observe the changing shape of these sunspots.
Sunspots are dark areas on the solar surface, contain strong magnetic fields that are constantly shifting. A moderate-sized sunspot is about as large as the Earth. Sunspots form and dissipate over periods of days or weeks. They occur when strong magnetic fields emerge through the solar surface and allow the area to cool slightly, from a background value of 6000 ° C down to about 4200 ° C; this area appears as a dark spot in contrast with the very bright photosphere of the Sun. The rotation of these sunspots can be seen on the solar surface; they take about 27 days to make a complete rotation as seen from Earth.
Sunspots remain more or less in place on the Sun. Near the solar equator the surface rotates at a faster rate than near the solar poles. Groups of sunspots, especially those with complex magnetic field configurations, are often the sites of solar flares. Over the last 300 years, the average number of sunspots has regularly waxed and waned in an 11-year (on average) solar or sunspot cycle.
The second segment of this movie shows the same period (January 7 through 15, 2013) but in Extreme Ultraviolet. This composite of three wavelengths (211, 193 and 171 angstroms) shows the crackling region coming over the Eastern limb of the Sun and then tracking across the center.
Credit: NASA SDO