Quasars are no longer so mysterious. Astronomers have suggested that they may arise when a massive star (or stars) explodes and collapses, forming an enormous gravitational field – a black hole – that serves as a source of energy. Or the gas and matter these supernovas spew forth may flow into an existing black hole near the galaxy’s center. The black hole might then flare into a quasar, which further stellar explosions creating its luminosity. Still another theory accounts for these bodies’ powerful radio-wave emissions. A quasar could be a pair of huge clouds filled with charged particles and surrounded by a strong magnetic field. The clouds would trap electrons shooting out from a plasma nucleus. This, in turn, would result in the emission of radio waves, which might vary, or pulse, as the nuclear ‘generator’ turned on and off.
Most astronomers support the theory that quasar is the extremely luminous nucleus of a galaxy. This nucleus surrounds a black hole whose gravitational force, when exerted in nearby stars, tears them apart and sucks in their gas and matter. This flow produces energy that is seen as a quasar. Spiral galaxies with luminous nuclei that radiate energy several billion times greater than that of our Sun – may indeed have quasar nuclei. Because quasars are so far away, they afford scientists a glimpse of the primordial universe soon after the Big Bang, when matter was more densely compacted.