The Hubble Classification This site provides an overview of the various types of galaxies. Visit the Galaxies web site
The Hubble Law On this site you will find a discussion of the Hubble Law and a simple "calculator" that allows you to find the distance to an object if you know its redshift and the Hubble constant. (In Chapter 18 we discuss the law's use in determining the age of the universe.) Visit the The Hubble Law web site
The Nature of Active Galactic Nuclei This Chandra site contains a wealth of good information about quasars and active galaxies. Visit the Active Galaxies web site
