Johns Hopkins
astrophysicist Adam Riess, who led the first study
revealing the
existence of a mysterious "dark energy" permeating the
universe, will share
one of the most prestigious prizes in cosmology, it was
announced last week.
The Peter Gruber Foundation said that its 2007
Cosmology Prize — a gold medal
and $500,000 — will be presented to two teams of
astrophysicists, the High-z
Supernova Search Team and the Supernova Cosmology
Project.
Riess, a professor in the Henry A. Rowland Department
of Physics and
Astronomy in the Krieger School of Arts and Sciences, is a
member of the High-z team. He led the study for which
High-z is being recognized, the first to show
that a previously unknown force, now called "dark energy,"
is driving the
universe to expand at an ever-increasing rate. The study
was published in
Astrophysical Journal in September 1998.
This is the second year that a Johns Hopkins
astrophysicist has shared the
Gruber Prize. Charles L. Bennett, a professor in Physics
and Astronomy, was one
of the leaders of the 18-member Cosmic Background Explorer
team, which won the
Gruber last year. The COBE satellite was developed by
NASA's Goddard Space
Flight Center to measure the early universe's now-diffuse
infrared and
microwave radiation.
Both of this year's teams are being honored for
discoveries involving
"dark energy," which is still not explained. Riess and
High-z SN overall
leader Brian Schmidt collaborated with other members of the
team on the highly
difficult and precise measurements — across 7 billion
light-years — that led to the
1998 discovery.
"Our aim was to use supernovae — a special kind
of exploding star — to measure
how fast the universe was expanding in the past and then to
compare it with how
fast it is expanding now," Riess said.
The team anticipated finding that gravity — the
attractive force that holds
things together — had slowed the universe's rate of
expansion over time. Instead,
the astronomers were startled to discern that the rate of
expansion is actually
accelerating.
"If you tossed a ball into the air and it kept right
on going up instead
of falling to the ground, you would undoubtedly be very
surprised. Well, that's
about how surprised we were with this result," said Riess,
who also is a
scientist at the Space Telescope Science Institute, located
on the Homewood
campus.
Those observations sent the team back to the idea
— first conceived by Albert
Einstein but later rejected as his "biggest blunder"
— that the so-called vacuum
of space might produce a sort of "anti-gravity" energy that
could act
repulsively and would accelerate the expansion of the
universe. Suddenly, that
idea made sense.
Riess and other experts in the field refer to the
phenomenon as "dark
energy" and posit that it may account for up to 70 percent
of the universe,
"even though," he confesses, "we still don't understand it
well at all."
Subsequent Hubble
Space Telescope observations by Riess and the High-z SN
team helped confirm the initial result in 2004. Riess,
Schmidt and Supernova
Cosmology Project leader Saul Perlmutter shared the
prestigious $1 million Shaw
Prize last year for this body of work.
Riess is a 1992 graduate of MIT, with a major in
physics and a minor in
history, and earned his doctorate in astrophysics from
Harvard University in
1996. From 1996 to 1999, during which time the initial
discovery was made, he
was a Miller Fellow at the University of California,
Berkeley. He has been an
astronomer with the Space
Telescope Science Institute since 1999 and joined the
faculty at Johns Hopkins in 2006.
The two competing teams and their leaders — the
High-z SN team, with Schmidt
of the Mount Stromlo Observatory of the Australian National
University in
Canberra, and the Supernova Cosmology Project, with
Perlmutter of the Lawrence
Berkeley Laboratory at the University of California,
Berkeley — will receive the
Gruber Prize at a ceremony on Sept. 7 in Cambridge,
England.
The annual Peter Gruber Foundation Cosmology Prize
recognizes fundamental
advances in research on the origin, development and
structure of the universe.
Co-sponsored by the International Astronomical Union, the
prize aims to
acknowledge and encourage further exploration in a field
that shapes the way we
perceive and comprehend the universe.