Oct 1 2007
From The Space Library
NASA announced that one of its STEREO satellites had recorded images of an April 2007 collision between a comet and a solar hurricane, marking the first time that scientists had observed such an event. Encke’s comet, traveling in the orbit of Mercury, had encountered a CME. NASA had designed STEREO to observe this type of solar event. As the CME swept by, the comet’s tail had brightened and then had disconnected, as the front of the ejection carried it away. Scientists had known that a comet’s plasma tail could disconnect from the comet, but the conditions necessary for this to occur had remained a mystery. Preliminary analysis of the images, which NASA researchers had combined into a movie, indicated that a phenomenon called magnetic reconnection had caused the tail to detach. In a magnetic reconnection event, the magnetic fields in a CME crunch together the oppositely directed magnetic fields around a comet, causing the comet fields to link together suddenly. This sudden reconnection releases a burst of energy that detaches the comet’s tail. Angelos Vourlidas of the U.S. Naval Research Laboratory in Washington, DC, was lead author of an article about the event, published in the 10 October 2007 issue of Astrophysical Journal Letters. Remarking on the researchers’ sense of awe when they viewed the images, Vourlidas described their surprise at seeing the disconnection of the tail, calling the event “the icing on the cake.”14
NASA, “NASA Satellite Sees Solar Hurricane Detach Comet Tail,” news release 07-214, 1 October 2007, http://www.nasa.gov/home/hqnews/2007/oct/HQ_07214_Comet_Collision.html (accessed 8 September 2010); Andrea Thompson, “Solar Storm Rips Tail Off Comet,” Space.com, 1 October 2007, http://www.space.com/scienceastronomy/071001_hurr_comet.html (accessed 27 September 2010).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
