Transcript: The fact that quasars are at large distances and have huge luminosities depends on the cosmological interpretation of their redshift. There are some crucial distinctions between galaxies and quasars as far as redshift goes. For galaxies they follow a Hubble relation where distance...

Transcript: Quasars were mysterious when they were first discovered in the 1960s. But careful work showed that the quasar is surrounded by nebulosity, and eventually spectroscopy of the nebulosity showed that it was the light of stars in a normal galaxy. Thus quasar stands for quasi-stellar...

Transcript: Astronomers at Caltech became interested in the newly accurate radio positions of strong sources in the sky. They focused in particular on two sources, 3C48 and 3C273 which appeared to be associated with bluish stars. Since normal stars like the Sun do not emit strong radio waves...