their distance from earth lies in between 600 million and 28.85 billion light years.
Thus the radiation that we are receiving now was emitted billions of years ago by
quasars. Hence they provide valuable insight into what newly formed galactic nuclei
looked like after the BIG BANG. This also shows that these luminous objects are
located at the edge of the universe.
A distant quasar powered by a massive black hole. Credit: "Artist's rendering ULAS J1120+0641" by
ESO/M. Kornmesser - Wikimedia Commons
Now when we talk about radiation from a system involving a black hole, one would
argue that the immense gravity of a black hole would not allow any radiation to
escape. But in case of quasars, the escaping energy for radiation is generated outside
the event horizon by gravitational stresses and immense friction on the incomin