The Royal Swedish Academy of Sciences has awarded the 2011 Nobel Prize in Physics to Saul Perlmutter, Adam Riess, and Brian Schmidt “for the discovery of the accelerating expansion of the universe through observations of distant supernovae.” Half the prize goes to Perlmutter (University of California, Berkeley), who organized the pioneering Supernova Cosmology Project in 1988. The other half is shared by Schmidt (Australian National University), who led the High-Z Supernova Search Team organized in 1994, and Riess (Johns Hopkins University), lead author of the team’s discovery paper.
Early in 1998 both teams reported independently that their observations of the redshifts z and apparent brightnesses of distant type Ia supernovae led to the completely unanticipated conclusion that the Hubble expansion of the cosmos was speeding up (see PHYSICS TODAY, June 1998, page 17). Surely, one would have thought, gravity must be slowing the cosmic expansion down. Researchers are rightly...
