26 July 2007

University of Texas at Austin Astronomer Shares $500,000 International Cosmology Prize

AUSTIN — University of Texas at Austin post-doctoral fellow Robert Quimby is among a group of scientists to receive this year’s Gruber Prize for Cosmology for the discovery that the universe is expanding at an accelerating rate.

The mysterious force behind the acceleration has been dubbed “dark energy.” The $500,000 prize will be divided among 53 scientists, mostly astronomers, composing two research groups.

“I performed the fits to the data that actually showed the mysterious expansion force existed,” Quimby says, “although I was just an undergrad at the time and I didn’t know what it meant or why it was a big deal. I’m sure glad I took that summer job now.”

Quimby was a member of the Supernova Cosmology Project team, headed by Saul Perlmutter of The University of California, Berkeley. Quimby worked on the project while an undergraduate at Berkeley and for two summers afterward (1997 to 2002). The team’s 31 scientists hail from Australia, Chile, France, Spain, Sweden, the United Kingdom and the United States.

He will receive his share of the prize, about $4,000, at a ceremony in Cambridge, England, in September.

Quimby completed his Ph.D. in astronomy at The University of Texas at Austin in December 2006. He garnered considerable acclaim for his discovery that fall of a new type of supernova, the brightest yet on record. He will begin a post-doctoral appointment with the California Institute of Technology this September where he will continue his search for brilliant explosions.

The members of the Supernova Cosmology Project are sharing the Gruber Prize with the High-z Supernova Search team, headed by Brian Schmidt of the Australian National University. That team’s 19 members come from the United States, the United Kingdom, Germany, Chile and Australia.

An accelerating universe was a crazy result that was hard to accept. Yet the two teams, racing neck and neck, simultaneously came to the same conclusion. Their discovery led to the idea of an expansion force, now known as dark energy. The two teams expected to find that the universe would either expand for a long while then contract, or it would expand forever but slow over the millennia.

To find out which, they not only needed to be able to measure the speed with which distant objects are traveling away from us, but also how far away they are. To measure the distance, they needed standardized light sources — very bright ones that would be visible to Earth-based telescopes despite being billions of light years away and billions of years old.

The standard light sources they used were exploding stars — in particular Type Ia supernovae. Finding them in the void at huge distances from Earth was not easy and the subsequent analyses turned up surprising results. For both teams it was not what they were expecting. For months they both tried to figure out where they had gone wrong, searching for any tiny source of error. In the end, the data were right. The accepted model of the universe was wrong, with dramatic implications. The acceleration suggests the fate of the universe is to just keep expanding, faster and faster.

The Gruber Prize honors a leading cosmologist, astronomer, astrophysicist, or scientific philosopher for theoretical, analytical or conceptual discoveries leading to fundamental advances in the field. Since 2001, the prize has been awarded in collaboration with the International Astronomical Union, the international umbrella organization for professional astronomers.

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Note to Editors: For more information, please see The Gruber Foundation press web site.