The 2011 Nobel Prize in Physics has been awarded to astrophysicists Saul Perlmutter, Brian P. Schmidt, and Adam G. Riess, for their discovery of the accelerating expansion of the Universe through observations of distant supernovae.
The researchers studied more than 50 distant supernovae — explosions of ancient stars — and found that their light was weaker than expected, a sign that the expansion of the Universe was accelerating. Scientists think that dark energy is driving the expansion. The researchers presented their findings in 1998.
The Nobel winners worked in two separate teams: Perlmutter headed up the Supernova Cosmology Project, which began in 1988, while Schmidt and Riess worked on the High-z Supernova Search Team from 1994.
Perlmutter, who has half the prize to himself, is at the Lawrence Berkeley National Lab in California.The other half is shared between Schmidt, who is at the Australian National University in Weston Creek, Australia and Riess, at Johns Hopkins University and the Space Telescope Science Institute in Baltimore, Maryland.
A 2003 Nature news feature, ‘Cosmology gets real’, explains how the Nobellists’ observations, and others that followed, started to provide rigorous data for theories about the universe. [Subscription required].
The supernovae that were studied at the time were Type 1a supernovae, the ‘standard candles’ (which have a known luminosity, so that their distance can be worked out from their observed brightness). Astronomers are hoping that other types of supernovae may join them as gauges of cosmic expansion, as this 2010 Nature story, ‘Alternative yardstick to measure the universe’, explains.
Read Nature’s full coverage of the physics prize here.
The key research papers for the result: