Comet Encke, de-tailed

Click on the image above to see a movie of the tail being ripped off a comet by a wall of plasma thrown off the sun. The comet in the image is Encke, a short period comet that orbits the sun every 3.3 years. The mechanism that removed the comet tail is not collisional but rather electromagnetic. Comets typically have two tails, a dust tail (the one seen by our eyes) that consists of dust particles thrown off the comet head and an ion tail that consists of electrically charged atoms and molecules thrown off the comet head. The imagery here shows the ion tail, which responds to magnetic fields. It is likely that as the solar plasma swept past it compressed the magnetic field within the comet's ion tail, causing it to reconfigure in such a way that the tail was severed from the comet head. The solar plasma strips off the tail, carrying it downstream (to the left in the image). The comet quickly forms a new ion tail near the end of the image sequence. Each frame in the movie is 45 minutes apart.