This is a closer view of Comet Encke's collision with a Coronal Mass Ejection (CME) as seen by the STEREO satellite on April 20, 2007. The collision is notable because it completely removed Encke's tail. The blue color here is a gradient added to help make the comet and CME more visible. Note: Closeup of Comet Encke Animator: Walt Feimer (HTSI). Scientist: Angelos Vourlidas (NRL). Platforms/Sensors/Data Sets: STEREO.