Shaw Prize for the Accelerating Universe

By Sean Carroll | June 26, 2006 8:54 am

The Shaw Prize in astrophysics has been awarded to Saul Perlmutter, Adam Riess, and Brian Schmidt, for discovering the acceleration of the universe by measuring the Hubble diagram using Type Ia supernovae. The Shaw Prize is relatively new, having first been given in 2004, and is awarded in three areas: Astronomy, Mathematical Sciences, and Life Sciences and Medicine. It comes with a total of US$1 million, split between the three recipients. Competitive with, although not quite as much as, the Nobel prize…

Brian Schmidt and Saul Perlmutter
Brian Schmidt and Saul Perlmutter come to blows over whose universe is accelerating faster

Brian was the leader of the High-Z Supernova Search Team and Adam was lead author on their paper; Saul was the leader of the Supernova Cosmology Project and also lead author on their paper. (Get some more inside scoop from Rob Knop.) To most of us, their finding was a complete surprise, as we were all quite familiar with the fine-tuning problems associated with the cosmological constant (the most straightforward explanation for the acceleration). But by 1998, it had become impossible to deny that something fishy was going on — the universe was not the simple matter-dominated flat Einstein-de Sitter cosmology of the standard Cold Dark Matter model. In late 1997 I was asked to give a review talk at a CMB conference in Santa Barbara, on the topic of “every way to measure the cosmological parameters other than the CMB.” In assembling the talk the overall message came through loud and clear, from considerations of the age of the universe, direct measures of the mass density, and properties of large-scale structure. There were plenty of ideas floating in the air, including an open universe (the most obvious choice), warm dark matter, a mix of hot and cold dark matter, or some dramatic features in the primordial power spectrum, as well as the old standby cosmological constant. But only the last of these solved all of the problems with one fell swoop. So when the two supernova groups announced in 1998 that they had direct evidence that there really was a cosmological constant, in the form of an accelerating universe, the community was primed to believe them, which they did fairly quickly. Soon thereafter, of course, improved measurements of the CMB anisotropies indicated that the universe was spatially flat, in perfect accord with the combined supernova and matter-density measurements. If you were to plot the inferred density of both matter and cosmological constant, the constraints from the three different techniques — supernovae, matter dynamics (clusters or large-scale structure) and the CMB — the allowed regions overlapped in perfect harmony.

Omega_M, Omega_Lambda

A preposterous universe, maybe, but I like it.


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] .


See More

Collapse bottom bar