Comets

	Closeup of Comet Encke from STEREO
	Comet Encke’s Tail Stripped Away by a CME On April 20, 2007, NASA's STEREO satellite captured the first images ever of a collision between a solar storm, called a coronal mass ejection (CME), and a comet.  Comet Encke had just dipped inside the orbit of Mercury, perilously close to the sun, when a CME struck and literally tore the comet's tail off.  This surely has happened to comets before, but for the first time in history a spacecraft was watching.