Despite their name, planetary nebulae have nothing to do with planets. They were described as such by early astronomers whose telescopes showed them as glowing disc-like objects, but we now know that they represent the final stage of activity of stars like our Sun. A way of estimating more accurate distances to planetary nebulae dispersed across our Galaxy has just been announced.
A spectacular galaxy collision has been discovered lurking behind the Milky Way, the closest such system ever found. “Kathryn’s Wheel” was found during a special wide field survey of the Southern Milky Way with the UK Schmidt Telescope in Australia. Such systems are very rare and arise from “bull’s-eye” collisions between two galaxies of similar mass.