Remember the hexagon surrounding Saturn's north pole
? Now for our delectation Ano_Nimass Coward sends us to Space.com for a look at a nebula with near perfect bilateral symmetry
surrounding a dying star. The so-called Red Square ranks among the most symmetrical objects ever observed by scientists. "If you fold things across the principle diagonal axis, you get an almost perfect reflection symmetry," said the leader of a study of the object, recently published in Science. A possible explanation for the structure's glow, if not its shape, was advanced in a paper appearing in PNAS, which attributes the glow of a similar object — dubbed, confusingly, the Red Rectangle — to exotic space-hardened organic molecules called Polycyclic Aromatic Hydrocarbons
. PAHs are normally unstable but may occur in places like the nebula in question, in nanostructured clusters that are extremely stable and radiation hardened.