4. Helix Nebula
(originally posted February 16, 2007)
Dust from comets that survived the death of their star is clouding the "eye" of the distant Helix nebula, as revealed by an image released by NASA's Spitzer Space Telescope on February 12.
The nebula, which lies about 700 light-years from Earth, is the colorful remnant of a dying sunlike star that cast off its outer layers to become a white dwarf
Similar nebulae litter our galaxy, but the Helix nebula is now among the few known to show evidence of cosmic survivors. A haze of red around the dead star at the center of the formation is most likely being caused by dust from colliding comets, NASA scientists concluded.
Before the star died, comets in the outer reaches of the system orbited in an orderly fashion. But as the dying star expanded, it blew these comets into each other's paths, so that they now jostle each other and send dust swirling around the white dwarf.
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Image courtesy NASA/JPL-Caltech/University of Arizona