The Sun as seen through SOHO’s extreme-ultraviolet imaging telescope at 01:06 GMT today, on the 20th anniversary of the satellite’s launch. The instrument images the Sun’s atmosphere at different wavelengths, showing solar material at different temperatures. The bright regions seen in this image correspond to temperatures of about two million degrees celsius.
More about SOHO’s images: http://sohowww.estec.esa.nl/data/realtime/image-description.html
More about SOHO’s anniversary: SOHO celebrates 20 years of discoveries