The Sun from TRACE in ultra-violet light

Caption NASA originale:"Shown in ultraviolet light, the relatively cool dark regions have temperatures of thousands of degrees Celsius. Large sunspot group AR 9169 is visible as the bright area near the horizon. The bright glowing gas flowing around the sunspots has a temperature of over 1.000.000° C. The reason for the high temperatures is still unknown but thought to be related to the rapidly changing magnetic field loops that "channel" solar plasma.
Sunspot group AR 9169 moved across the Sun during September 2000 and decayed in a few weeks".