A Hubble diagram graphs the redshift of galaxies (or other distant objects) against their distance, for a set of galaxies whose distance has been determined by other means. The original Hubble diagram was a graph created by Edwin Hubble to demonstrate that galaxies are moving away from each other in a certain pattern. It demonstrated that the rate of spreading was constant among the galaxies, now known as Hubble's law, and a measure of the rate being the Hubble constant. Hubble diagrams are still created using newer techniques and accuracy in determining the distances to galaxies, such as the use of Type Ia supernova standard candles (a supernova Hubble diagram or SN Hubble diagram). Current interest is not only to refine the measurement of the Hubble constant but to look for variation, e.g., the study that brought dark energy to light.