Quasars

A Quasar a the centre of its host galaxy

© STSci (HST)

They are probably the brightest objects in the universe - many times brighter than normal galaxies.

They are so far away that they look like stars rather than big fuzzy galaxies.

This makes them looks like single stars, even though they are not - the name Quasar stands for QUAsi-StellAR (which means "like a star, but not really one"!)

We think that they are so bright because they have super-massive black holes in the centre. This black hole is so big that it is "eating up" all the stars around it, destroying them and making lots of huge explosions all the time.

There is a lot we do not know about Quasars. In particular, why are they all so far away?