so says the galaxies we see around us now may have been quasars in the distant past; even our Milky Way galaxy may have been a quasar-like galaxy long ago, now not much material falls into the large black hole at the Milky Way's center, so the radiation output from the center is not as great as it used to be. How difficult are quasars to study? Not all that difficult, if you have a huge telescope such as the Hubble Space Telescope.The Hubble Space Telescope has shown that quasars live in a remarkable variety of galaxies, many of which are violently colliding. This complicated picture suggests there may be a variety of mechanisms some quite subtle for turning on quasars, the universes most energetic objects. Hubble researchers are also intrigued by the fact that the quasars studied do not appear to have obviously damaged the galaxies in which they live. This could mean that quasars are relatively short lived phenomena which many galaxies, including the Milky Way, experienced long ago. John Bahcall of the Institute for Advanced Study, Princeton, NJ, emphasizes that Hubble's clarity opens a complicated picture. The basic assumption was that there was only one kind of host galaxy, or catastrophic event, which feeds a quasar. In reality we do not have a simple picture, we have a mess. Mike Disney, University of Wales College, Cardiff, U.K., who is a leader of the European team, says, "People had suspected that collisions might be an important mechanism for feeding black holes and generating the vast amounts of energy emitted by quasars. Now we know they are and we didn't know that before Hubble. Although a number of images obtained through the use of the Hubble Telescope show collisions between pairs of galaxies, which could trigger the birth of quasars, some pictures reveal apparently normal, undisturbed galaxies possessing quasars. The beauty and clarity of the Hubble images, as well as the diversity of quasar environments amazed...
