So what exactly are quasars made up of?
I doubt very much that this is true.
Actually I read that phrase from thisI doubt very much that this is true.At first the astronomers thought they were stars, but further observations showed that they were not stars.
A good reference on the history is here:
The discovery of quasars in 1963, and more generally, active galactic nuclei (AGN), revolutionized extragalactic astronomy. In early February 1963, Maarten Schmidt (b. 1929; Figure 1) ...