In 1929 Edwin Hubble discovered that our Universe is expanding. Eighty years later, the Space Telescope that bears his name is being used to study an even more surprising phenomenon: that the expansion is speeding up.
The origin of this effect is not known but is broadly attributed to a type of “dark energy” first posited to exist by Albert Einstein and now dominating the mass-energy budget of the Universe. Professor Riess will describe how his team discovered the acceleration of the Universe and why understanding the nature of dark energy presents one of the greatest remaining challenges in astrophysics and cosmology.
He will also discuss recent evidence that the Universe continues to defy our best efforts to predict its behaviour.
Professor Adam Riess is an American astrophysicist.Bloomberg Distinguished Professor at Johns Hopkins University and the Space Telescope Science Institute. Riess shared the 2011 Nobel Prize in Physics with Saul Perlmutter and Brian Schmidt "for the discovery of the accelerating expansion of the Universe through observations of distant supernovae".
Riess jointly led the study with Brian Schmidt in 1998 for the High-z Supernova Search Team which first reported evidence that the Universe's expansion rate is now accelerating through monitoring of Type Ia Supernovae. The team's observations were contrary to the current theory that the expansion of the universe was slowing down; instead, by monitoring the color shifts in the light from supernovas from Earth, they discovered that these billion-year old novae were still accelerating. This result was also found nearly simultaneously by the Supernova Cosmology Project, led by Saul Perlmutter.
The corroborating evidence between the two competing studies led to the acceptance of the accelerating universe theory, and initiated new research to understand the nature of the universe, such as the existence of dark energy. The discovery of the accelerating universe was named 'Breakthrough of the Year' by Science Magazine in 1998, and Riess was jointly awarded the 2011 Nobel Prize in Physics along with Schmidt and Perlmutter for their ground-breaking work.