SOHO: Solar and Heliospheric Observatory

http://sohowww.nascom.nasa.gov/gallery/images/superprom.html

EIT 304Å image of a huge, handle-shaped prominence taken on Sept. 14, 1999 --
Prominences are huge clouds of relatively cool dense plasma suspended in the
Sun's hot, thin corona. At times, they can erupt, escaping the Sun's
atmosphere. Emission in this spectral line shows the upper chromosphere at a
temperature of about 60,000 degrees K. Every feature in the image traces
magnetic field structure. The hottest areas appear almost white, while the
darker red areas indicate cooler temperatures.