Adam Riess

Adam Riess was a lead author on the 1998 study that used observations of distant Type Ia supernovae to demonstrate that the expansion of the universe is accelerating, rather than slowing down as previously assumed. This discovery pointed to the existence of dark energy, a repulsive force driving the acceleration, and fundamentally transformed the field of cosmology.

Riess shared the 2011 Nobel Prize in Physics with Saul Perlmutter of UC Berkeley and Brian Schmidt of the Australian National University. Perlmutter led the Supernova Cosmology Project, while Riess and Schmidt led the competing High-z Supernova Search Team, both of which independently discovered the accelerating expansion.

The SH0ES project (Supernovae, H0, for the Equation of State) is a research program led by Riess that uses the Hubble Space Telescope to measure the Hubble constant with increasing precision. The project's results have revealed a persistent discrepancy between the locally measured expansion rate and the value predicted by cosmic microwave background observations, known as the 'Hubble tension.'

Adam Riess is a professor of astronomy and physics at Johns Hopkins University and a distinguished astronomer at the Space Telescope Science Institute in Baltimore, Maryland. He has been affiliated with Johns Hopkins since completing his postdoctoral fellowship at UC Berkeley.