1998: Saul Perlmutter and Brian Schmidt Discover Runaway Universe

Image of Saul Perlmutter. Courtesy of Lawrence Berkeley National Laboratory.

The 20th century was an amazing period of discovery for cosmology—the existence of galaxies, the expansion of the universe, vast sheets and walls of galaxies, and an image of the afterglow of the Big Bang, before stars and galaxies had started to form.  Yet the end of the century held one more surprise. The universe was not just expanding—it was accelerating!  This finding would not have been believed were it not confirmed by two teams working at the same time, and finding the same unbelievable result.  One team was headed by Saul Perlmutter at Lawrence Berkeley National Laboraotry in California.