Quasars are the most distant and brightest objects in the known universe. The word quasar stands for quasi-stellar radio source. Most Quasars, however, have a very low level of radio activity.

Quasars are very bright objects that are powered by Black Holes at the center

ESO/L. Calçada

When the light emitted from Quasars was analysed it realised that they have a very large redshift meaning that they are travelling away from us at a very high velocity.

It is thought that the extremely high energy levels are due to Quasars being super-massive black holes with millions of time more mass than our own sun.