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Comets 101: A primer on the 'dirty snowballs' of space

By: Katherine Butler on Jan. 11, 2012, 10:35 a.m.
Helix nebula

Photo: NASA/JPL-Cal-Tech/U. of Arizona

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Comet kicks up dust in the Helix nebula

While comets may seem tiny and insignificant compared to a star, their influence is felt all around the galaxy. Here we see the Helix nebula imaged by the Spitzer Space Telescope. The Helix nebula is located 700 light-years away in the constellation Aquarius. It is a planetary nebula that houses the remains of a star that once resembled our own. NASA describes this image this way: “The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star.” When this star died, the resulting explosion likely threw comets and planets together into a cosmic dust storm. This is one of the few examples in space where comets have survived the destruction of their star, according to NASA.