Explanation [from the site]: Aloha and Season's greetings! On December 22nd, at 01:14 Universal Time(December 21, 3:14pm Hawaii-Aleutian Standard Time), the Sun reaches its southernmost point in planet Earth's sky markingthe final season changefor the year 2002. In celebration, considerthis delightfully detailed, brightly colored image of the active Sun. From the EIT instrumentonboard the space-based SOHO observatory, the tantalizing picture is a false-color composite of three images all made in extreme ultraviolet light. Each individual imagehighlights a different temperatureregime in the upper solar atmosphereand was assigned a specific color; red at 2 million, green at 1.5 million, and blue at 1 million degrees C. The combined image shows bright active regions strewn across the solar disk, which would otherwise appear as dark groups of sunspots in visible light images, along with some magnificent plasma loops and an immense prominenceat the righthand solar limb.
I bet this picture in poster-size would be a hot item. Click the photo for the source site.