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News Release 19 of 44

July 17, 2007 07:00 PM (EDT)

News Release Number: STScI-2007-29

Gruber Cosmology Prize Awarded to STScI Dark Energy Discoverers

The full news release story:

Gruber Cosmology Prize Awarded to STScI Dark Energy DiscoverersView this image

Four astronomers at the Space Telescope Science Institute (STScI) in Baltimore, Md. are on two teams sharing the 2007 Gruber Cosmology Prize for their discovery that the expanding universe is accelerating under a mysterious cosmic force called dark energy.

The astronomers are Andrew Fruchter, Ronald Gilliland, Nino Panagia, and Adam Riess. Riess is also Professor of Physics at Johns Hopkins University.

Gilliland and Riess are on the High-z Supernova Search Team led by Brian Schmidt of the Australian National University. Riess is the leader of the study for which his team is being honored.

"I am happy to see the High-z Team honored for this work. I think this discovery represents the end of the beginning for cosmology. The universe's constituents have now been plumbed, though their nature remains a mystery," said Riess.

Gilliland noted, "I was very fortunate a dozen years ago to have been invited to join the High-z collaboration to assist in transitioning the most demanding observations to the Hubble Space Telescope. It is immensely gratifying to see this award recognize the dedication and excellence of the High-z Supernova Search Team."

Fruchter and Panagia are on the Supernova Cosmology Project team led by Saul Perlmutter of the University of California at Berkeley.

"I am pleased and honored to be recognized as a member of one of the teams that made the amazing discovery that the universe appears to be accelerated. Personally, the main lesson I have learned from this discovery is that in science we better keep our eyes well open all the time because nature does not feel obliged to comply with our misconceptions, and often the unthinkable is the truth," said Panagia.

"I feel extremely fortunate to have been involved in this work. The two teams honored here have found one of the most surprising results in the history of science. The open question is whether the final explanation of our observations will be even more astonishing," said Fruchter.

The $500,000 prize will be shared: by Schmidt, Perlmutter, and their two teams, which included 51 co-authors between the two key discovery papers published (Riess et al. 1998, AJ, 116, 1009, and Perlmutter et al. 1999, ApJ, 517, 565).

The prize will be awarded at the University of Cambridge on September 7.

The two teams independently found that the universe is expanding at an ever faster rate. This means that an unknown form of energy in space, called dark energy, is overcoming the pull of gravity among galaxies to make the universe expand ever faster.

To be able to measure the universe's expansion rate, now and at various times in the distant past, they needed standardized light sources. These sources have to be 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 called Type Ia supernovae. The researchers used the unique sensitivity of NASA's Hubble Space Telescope to make precise measurements of these distant supernovae; a task that would have been impossible with only ground-based telescopes.

Remaining doubts that supernovae were providing an accurate history of the universe were greatly alleviated in 2004 when the Higher-z Team, a follow-up group to the High-z Team that is led by Riess, used the Hubble Space Telescope to extend the supernova measurements well into the period preceding the present acceleration.

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.

Since 2001, the Cosmology Prize has been awarded in collaboration with the International Astronomical Union. The Foundation's other international prizes are in Genetics, Neuroscience, Justice and Women's Rights. Nominations for the 2008 prizes are now open and close on December 31, 2007.


For additional information, contact:

Andrew Fruchter
Space Telescope Science Institute, Baltimore, Md.

Ronald Gilliland
Space Telescope Science Institute, Baltimore, Md.

Nino Panagia
Space Telescope Science Institute, Baltimore, Md.

Adam Riess
Space Telescope Science Institute/Johns Hopkins University, Baltimore, Md.