The word "quasar" is short for quasi-stellar objects, ie object that resembles stars. About 1960 astronomers found objects that were emitting energy in the radio band, and they named them radiostars and were later renamed to quasars. When they had a look at the spectrum from a radiostar they could see that it looked different from all others. It showed that the most common substance in it was nitrogen but in this spectrum the lines were in a different place than usual. This could be because of the expansion of our universe, but if this is the case the quasars must be heading away from us at enourmous speeds.

Another question without a satisfying answer is how far away are the quasars? The problem here is that it seems as if they are very far away from our galaxy, the Milky way. But if this is the case how can those objects radiate the amount of energy that is needed over those long distances? This means that a quasar must generate as much energy as a hundred galaxies or more. It also seems as if they are quite small which makes each observation even stranger.

At the moment we can only try to explain how quasars work and the mechanisms behind them, and there are many theories. However we don't know enough to have a good answer yet.