investigators.Discovered only 33 years ago, quasars are among the most baffling objects in the universe because of their small size and prodigious energy output. Quasars are not much bigger than Earth's solar system but pour out 100 to 1,000 times as much light as an entire galaxy containing a hundred billion stars. A super massive black hole, gobbling up stars, gas and dust, is theorized to be the engine powering a quasar. Most astronomers agree an active black hole is the only credible possibility that explains how quasars can be so compact, variable and powerful. Nevertheless, conclusive evidence has been elusive because quasars are so bright they mask any details of the environment where they live.These problems could not be solved without the Hubble Telescope. Observations by the European team, using the Wide Field Planetary Camera (WFPC2) in high resolution mode, reveal that quasars appear to be born in environments where two galaxies are interacting violently and probably colliding. This had long been suspected as a mechanism for igniting a quasar, but no one knew whether the idea was really right before the Hubble. In nearly every quasar we look at we clearly see one galaxy apparently swallowing another . Disney selected three quasars known to be strong infrared emitters, suggesting that they might be in spiral galaxies, which typically contain an enormous amount of gas and dust. When we image them with Hubble we see the most colossal smashups, where two giant spiral galaxies like our own Milky Way have crashed head on into one another and flung off pieces violently in all directions. Some of those bits seem to have finished up in the nucleus of one of the spirals where there is probably a giant black hole feeding on it. Both teams agree that Hubble images do show conclusively:1.That most quasars lie at the cores of luminous galaxies, both spiral and elliptical. Though underlying galaxies were suggested in ground-bas...
