The NASA/ESA Hubble Space Telescope has imaged a set of enigmatic quasar ghosts — ethereal, looped structures glowing green that orbit their host galaxies marking the graves of quasars that flickered to life and then faded. They offer new insights into the turbulent pasts of these galaxies.
Most galaxies age slowly as they run out of raw materials needed for growth over billions of years, but a pilot study has found some might shoot out this gas early on, causing them to redden and die prematurely.