At first appearance, quasars appear to be stars. On closer inspection, it is found that their redshift of their emitted light is great enough to place them as the most distant objects in the universe. For them to be visible at such distances, they have to be very bright and highly energetic, far more so than any star known, so they have been dubbed quasi-stellar objects.

The spectrum emitted by quasars shows that they are travelling incredibly fast away from us. On standard assumptions, then, they are some of the oldest objects that we can see.

Today the nature of quasars is not yet understood, and they are a dynamic area of research.

For more information on quasars, see

Bill Keel's WWW Gallery - Active Galaxies and Quasars
Quasars from Lake Afton Public Observatory
Quasars: "The Light Fantastic"