SDO view of the Sun eclipsed by Earth. The Solar Dynamics Observatory (SDO) is an Earth-orbiting spacecraft launched in 2010 by NASA and used to observe the Sun. Here, the Sun is seen at a wavelength of 304 angstroms (extreme ultraviolet). This channel shows areas where cooler, dense plumes of plasma occur above the visible surface of the Sun, and are seen in the upper chromosphere and lower transition region. The bright areas show high-density regions of plasma. Image obtained on 6 September 2012, at one of the two times each year that Earth blocks the SDO's view of the Sun.