Cosmic Backlighting: Distant Quasar Lights Up Galactic Halo | Video

The heat from newborn stars creates a halo of gas around its parent galaxy. When a distant galaxy's black hole-powered light is absorbed by the gas, the Hubble Space Telescope's Cosmic Origins Spectrograph (COS) can detect it.
credit : ESA / Hubble / Mash Mix: SPACE.com