What do quasars tell us about the universe?

Modern large galaxy surveys  have been carried out over the past decade or more and with the use of robotic computer driven telescopes have been able to amass large samples of data on very large numbers of galaxies in the Universe. These surveys supply, via a website, data that anyone with a little knowledge can download and analyze for themselves and as a result test their own cosmology. Among that data, for example, are specifications on the type of object (galaxy, quasar etc), its position on the sky, its redshift, and its brightness (which is given in magnitude units).  (The following is a bit technical but very interesting nonetheless.) Continue reading