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Panofsky Fellow Helps Win 2007 Gruber Cosmology Prize

It was a crazy result that was hard to accept. Yet, two teams, racing neck and neck, simultaneously came to the same conclusion. And because of their work we’ve come to realize that most of the universe is dark energy. As a result, the universe is likely to just keep expanding, faster and faster.

This year's Gruber Cosmology Prize has been awarded to Brian Schmidt and his High-z Supernova Search team—which includes the Kavli Institute for Particle Astrophysics and Cosmology's Saurabh Jha—and Saul Perlmutter and his Supernova Cosmology Project. The two groups will receive the prize for their discovery that the expansion of the Universe is accelerating.

The two teams expected to find that the universe would either expand then contract, or it would continue to expand then slow down over the millennia. But to find out, they needed to be able to measure the speed at which distant objects were traveling away from us—now and at various times in the distant past. And to do this 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. But finding them wasn’t easy. Then the analyses over the results turned up very surprising results. “The data wasn’t behaving as we thought it would,” said Schmidt. “There was a lot of nervous laughter,” said Perlmutter. 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. But the data was right. The accepted model of the universe was wrong.

Today Perlmutter, Schmidt and their colleagues continue to explore the implications of their work. Schmidt is planning the SkyMapper project, a telescope to map the southern sky. Perlmutter is working with a team including scientists at SLAC on the SuperNova/Acceleration Probe (SNAP), a satellite mission that would study the nature of dark energy.

The $500,000 prize will be shared in four parts: by Schmidt—at the Australian National University; Saul Perlmutter—at the University of California, Berkeley; and the two teams, which included fifty-one co-authors between the two key papers.

The Cosmology Prize honors a leading cosmologist, astronomer, astrophysicist or scientific philosopher for theoretical, analytical or conceptual discoveries leading to fundamental advances in the field.

—SLAC Today, July 18, 2007