Dr. Adam 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 1a Supernovas. 
Riess will share his insights into the nature of the universe, such as the existence of dark matter and his breakthroughs along the way.  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 groundbreaking work.