Quasars And Hubble Constant/Law

        Got home and went on my evening walk re-listening to an astronomy lecture on Quasars (quasi stellar radio source). A quasar is a supermassive black hole with the output of one trillion Suns and lies in the center of galaxies with a very high redshift making it very far (billions of light years) away taking it almost to the beginning of the Big Bang, some 13.7 billion years ago. This gets into the expansion of the universe and where the Hubble Constant/Law of the expansion rate of 72 kilometers for each megaparsec begins to fail at these very large distances. Quasars are powered by an accretion disk formed around the black hole where mater spirals in creating energetic electromagnetic radiation from a small area that out shines the galaxy which it resides.