This image of the sun was taken in extreme ultraviolet with the Solar and Heliospheric Observatory's (SOHO) Extreme Ultraviolet Imaging Telescope (EIT). They are composite iamges take at various wavelengths because different solar features are brought out at each wavelength. This image shows an arc-shaped prominence in the upper right-hand quadrant. A prominence is a large, dense, gaseous cloud of plasma that is relatively cool when compared to the hot thin corona of the Sun that surrounds it. Sometimes these clouds can escape the Sun's atmosphere when they erupt.