This interactive is used in Chapter 26.
The Cosmology Interactive allows you to play with the equations for the evolution of the Universe. You will see how the universe might evolve under certain parameters, such as the Hubble Constant and the density parameter Omega. You will see a representation of the Universe's evolution in terms of the expansion or collapse of a uniform distribution of galaxies in a window viewer in the upper right. Notice how the color of the galaxies change from red when they are expanding away from each other (redshifting) to blue (blueshifting) when they collapse back toward each other in Omega > 1 Universes.