Adam Riess received last year's Nobel Prize in physics for discovering the accelerating expansion of the universe, and discusses how this phenomenon is widely attributed to the elusive concept of dark energy.
Dr. Adam G. Riess is a Professor of Astronomy and Physics at the
Johns Hopkins University and a Senior member of the Science Staff at
the Space Telescope Science Institute, both in Baltimore, MD.
His research involves measurements of the cosmological framework with
supernovae (exploding stars) and Cepheids (pulsating stars).
In 1998 Dr. Riess led a study for the High-z Team which provided the
first direct and published evidence that the expansion of the Universe
was accelerating and filled with Dark Energy (Riess et al. 1998, AJ,
116, 1009), a result which, together with the Supernova Cosmology
Project's result, was called the Breakthrough Discovery of the Year by
Science Magazine in 1998.
On the ten year anniversary of this discovery, Symmetry Magazine
reprinted the key page from his lab notebook showing the first
indication that the expansion of the Universe was accelerating.
He followed this work with a number of studies to test the
susceptibility of this measurement to contamination by unexpected types
of dust or evolution. To this aim, Dr. Riess led the Hubble Higher-z
Team beginning in 2002 to find 25 of the most distant supernovae known
with the Hubble Space Telescope, all at redshift greater than 1. This
work culminated in the first highly significant detection of the
preceding, decelerating epoch of the Universe and helped to confirm the
reality of acceleration by disfavoring alternative,
astrophysically-motivated explanations for the faintness of supernovae
(Riess et al. 2004, ApJ, 607, 655).
This work also began characterizing the time-dependent
nature of dark energy. It has been identified by NASA as the #1
Achievement of the Hubble Space Telescope to date.
He was awarded the 2011 Nobel Prize in Physics for his contributions to the discovery of the acceleration of the expansion of the universe.