Relativistic jets are extremely powerful jets of plasma which emerge from the centers of some active galaxies, notably radio galaxies and quasars. Their lengths can reach several thousand or even hundreds of thousands of light years. It is believed that the twisting of magnetic fields in the accretion disk collimates the outflow along the rotation axis of the central object, so that when conditions are suitable, a jet will emerge from each face of the accretion disk. If the jet is oriented along the line of sight to earth, relativistic beaming will change its apparent brightness. The mechanisms for the creation of jets and the composition of jets are still a matter of much debate in the scientific community. It is believed that the jets are composed of an electrically neutral mixture of el