Discovery Teams of Dark Energy & Accelerating Universe Recognized
Astronomers now recognize that the eventual fate of the
universe is inextricably tied to the presence of dark energy and dark
matter.
Two teams of astronomers responsible for the historic discovery of dark energy received the 2007 $500,000 Gruber Cosmology Prize because “the discovery of the accelerated expansion has radically changed our perception of cosmic evolution.
The two teams of astronomers who observed the accelerating expansion include
Brian Schmidt of Australian National University and the High-z
Supernova Search team and Saul Perlmutter (University of California at
Berkeley) and
the Supernova Cosmology Project. “I think this discovery represents the end of the beginning for
cosmology,” said Adam Riess, Johns Hopkins University and Space
Telescope Science Institute, who led the study for which the group is
being honored. “The universe’s constituents have been plumbed, though
their nature remains a mystery.”
In 1997, the High-z team’s analysis of observations of distant
exploding stars first showed evidence that the expansion of the
universe is speeding up. That discovery flew in the face of common
wisdom that the universe’s expansion should be slowing due to gravity.
The team examined so-called Type Ia supernovae, which act as
“standard candles” since their intrinsic brightness is known. By
measuring the observed brightness and recession velocity due to cosmic
expansion (or redshift), astronomers can calculate the distance to the
supernova. Their calculations showed that the farthest supernovae were
dimmer than expected, and therefore more distant than expected. As a
result, the universe had to be expanding faster than expected.
“When Adam Riess told me what the data were saying, late in
1997, I could not believe it,” said Harvard University's Clowes Professor of Science, Robert Kirshner, leader of the Harvard supernova group. “We double-checked the
analysis and got the same answer. That’s when the horrible truth dawned
on me: we had a result that was going to turn this field upside down.” In the nine years that followed, study after study has confirmed the
findings of the High-z Supernova Search team and the Supernova
Cosmology Project. The current standard model for cosmology describes a
universe that is 70 percent dark energy, 25 percent dark matter, and
only 5 percent normal matter.
“I am still trying to come to grips with our discovery of an
accelerating universe,” said Schmidt. “It didn’t make much sense in
1998, and the whole notion of dark energy that seems to make up most of
our universe is still very foggy.”
“We don’t know what the dark energy really is, and we don’t
know what the dark matter really is,” summarized Kirshner. “We’ve got a
lot of work still to do!” Posted by Casey Kazan The full list of High-z Supernova Search team members who will
share the Cosmology Prize, and their current affiliations, is Brian
Schmidt (Australian National University), Peter Challis (Harvard
University), Alejandro Clocchiatt (Pontificia Universidad Catolica de
Chile), Alan Diercks (Institute for Systems Biology, Seattle), Alexei
V. Filippenko (University of California, Berkeley), Peter M. Garnavich
(University of Notre Dame), Ronald L. Gilliland (Space Telescope
Science Institute), Craig J. Hogan (University of Washington), Saurabh
Jha (Stanford Linear Accelerator Center), Robert P. Kirshner, (Harvard
University), Bruno Leibundgut (European Southern Observatory), Mark M.
Phillips (Carnegie Observatories), David Reiss (Institute for Systems
Biology. Seattle), Adam G. Riess (Space Telescope Science Institute),
Robert A. Schommer (Deceased),
R. Chris Smith (Cerro Tololo Inter-American Observatory, Chile), Jason
Spyromilio (European Southern Observatory), Christopher Stubbs (Harvard
University), Nicholas B. Suntzeff (Texas A&M University), and John
L. Tonry (Institute for Astronomy, Honolulu). Posted by Casey Kazan. Related Galaxy posts: "Beyond Einstein": Search for Dark Energy of the Universe "42" -Hitchhiker's Guide to the Galaxy Foreshadows Actual Weight of Universe
1st 3-D Map of the Universe's Dark Matter
Cosmic Collision Sheds Light on Mystery of Dark Matter
GAIA -Mapping the Family Tree of the Milky Way
New, Revised Hitchhiker's Guide to the Galaxy
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