Quasars. When I was young I, along with millions of other kids, looked up at the sky in wonder, and wanted to know more about the universe in which our tiny planet resides. I learned about the solar system, about our galaxy, about stars an nebulae, and even about black holes. But the one thing which captured my imagination was the Quasar. Moving fantastically fast, astonishingly bright, and a long way from the Earth, the mystery of the Quasar was a thing of wonder to me.
More is known now about these illusive objects. Originally known as 'Quasi-steller Objects', Chinese-born US astrophysicist Hong-Yee Chiu shortened the name to the more manageable Quasar. Discovered in the late 1950's using radio telescopes, the first Quasars were thought to be stars. They were later discovered to something very different.
Current thought has it that Quasars have what are called 'Supermassive Black Holes' at their centres. The energy that escapes from the Quasars is generated beyond the event horizon, and is thus able to be expelled. Quasars are small, smaller than the orbit of Neptune, as they are able to shift luminosity levels quickly.
When, in 1963, Maarten Schmidt studied the spectrum of 3C 273 (the first Quasar to be discovered, which can be seen in Virgo) he saw that the spectral lines did not fit with any know substances. The reson for this, discovered some time later, was that there was a large red shift in the spectrum. The substances were actually Hydrogen. This red-shift, as described in the Doppler effect, that the object being observed is moving away from the observer. Given the size of the red shift, it was concluded that these objects must be moving very fast. In fact, 3C 273 was later shown to be over 2,000 milllion light years away, and moving at almost 48,000 km/s.
There are many types of Quasar known to scientists now, the two shown in the picture above fr example, and even double quasars have been seen. There aren't any Quasars near us, which, given what's inside them is probably a good thing! Hopefully more will be known about them, as they could hold clues to the nature of the early universe.