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John Tonry Shares Major Astronomy Prize

IfA astronomer John L. Tonry is a member of a research team that has won the $500,000 Gruber Cosmology Prize for the discovery that the expansion of the Universe is accelerating.

Two teams of astronomers, one led by Brian Schmidt (Australian National University) and the other led by Saul Perlmutter (University of California, Berkeley), set out to look for evidence that the expansion of the Universe was slowing down as a result of gravitational forces between the galaxies. To everyone's surprise, both teams discovered that the expansion of the Universe is apparently accelerating, and that the Universe will expand forever.

The force that is causing the Universe to expand at an ever-increasing rate has been dubbed "dark energy," but its nature is a great mystery.

Tonry's particular contribution was the 1997 discovery of crucial supernovae explosions in distant galaxies using the Canada-France-Hawaii Telescope on Mauna Kea. He explains, "It was the CFHT data coupled with data from the Keck Observatory and the Hubble Space Telescope that were the key to identifying the accelerating Universe."

The Gruber Cosmology Prize honors a leading cosmologist, astronomer, astrophysicist or scientific philosopher for theoretical, analytical or conceptual discoveries leading to fundamental advances in the field. The teams received the prize at a ceremony at the University of Cambridge on September 7.