700 light years away in the constellation of Aquarius lies the Helix nebula, the expanding shell of gas from a dying star. This nebula is huge, 2.5 light years across, and so close that it's roughly the same size as the full Moon in the sky!
Spitzer's ability to see in the infrared becomes critical here; even though this is a well-studied nebula, this view of IR light invisible to our eyes reveals something never seen before in the Helix: a circular disk of dust surrounding the star (seen as the red circle immediately outside the star). Astronomers think this dust may have come from trillions of comets that orbited the star; they would've been vaporized when it expanded into a red giant.
The tendrils on the outer ring ironically look like comets but are actually caused when the hot, fast stellar wind from the central star caught up and collided with a slower, denser wind ejected earlier by the star. The gas fragmented in the collision, forming clumps, which erode away and blow off those long tails as the hot wind eats into them. To give you a sense of scale, each one of those clumps is bigger than our solar system, and the tails are a hundred billion kilometers long! Original blog postOriginal press releaseImage credit: NASA/JPL-Caltech/K. Su (Univ. of Arizona)