Credit: Solar Dynamics Observatory/NASA
Numerous coronal loops are visible in this ultraviolet view of the Sun. This image was captured by NASA's Solar Dynamics Observatory (SDO) satellite on April 20, 2012. This picture shows the Sun in extreme ultraviolet "light" with a wavelength of 17.1 nanometers (171 Ångstroms). UV images such as this highlight features in the solar corona - the Sun's upper atmosphere - with temperatures around one million degrees Celsius (about 1,800,000° Fahrenheit).