- The ethereal wisps in these images were illuminated, perhaps briefly, by a blast of radiation from a quasar — a very luminous and compact region that surrounds a supermassive black hole at the centre of a galaxy.
- In each of these eight images a quasar beam has caused once-invisible filaments in deep space to glow through a process called photoionisation.
- These ghostly structures are so far from the galaxy’s heart that it would have taken light from the quasar tens of thousands of years to reach them and light them up. So, although the quasars themselves have turned off, the green clouds will continue to glow for much longer before they too fade.
Hubble finds ghosts of quasars past
4. 3. 15 by Chadd Owens