Adam Riess

Intro American Nobel laureate
A.K.A. Adam Guy Riess
Is Astronomer Professor Scientist Physicist Astrophysicist
From United States of America
Type Academia Science
Gender male
Birth 16 December 1969, Washington, D.C., USA
Star sign Sagittarius

Adam Guy Riess (born December 16, 1969) is an American astrophysicist and Bloomberg Distinguished Professor at Johns Hopkins University and the Space Telescope Science Institute and is known for his research in using supernovae as cosmological probes. Riess shared both the 2006 Shaw Prize in Astronomy and the 2011 Nobel Prize in Physics with Saul Perlmutter and Brian P. Schmidt for providing evidence that the expansion of the universe is accelerating.


Riess was born in Washington, D.C., one of three children. He grew up in Warren, New Jersey, where his father (Naval engineer Michael Riess) owned a frozen-foods distribution company, Bistro International, and his mother (Doris Riess) worked as a clinical psychologist. Michael Riess (1931–2007) immigrated to the United States with his parents (journalist, war correspondent and author Curt Riess and Ilse Posnansky) from Germany on the ship SS Europa (1928) in 1936. Adam Riess has two sisters— Gail Saltz, a psychiatrist, and Holly Hagerman, an artist. Riess married Nancy Joy Schondorf in 1998.


He attended Watchung Hills Regional High School, graduating in the class of 1988. He also attended the prestigious New Jersey Governor's School in the Sciences in 1987. Riess then graduated from The Massachusetts Institute of Technology in 1992 where he was a member of the Phi Delta Theta fraternity. He received his PhD from Harvard University in 1996; it resulted in measurements of over twenty new type Ia supernovae and a method to utilize Type Ia supernovae as accurate distance indicators by correcting for intervening dust and intrinsic inhomogeneities. Riess' PhD thesis was supervised by Robert Kirshner and William H. Press and won the Robert J. Trumpler Award in 1999 for PhD theses of unusual importance to astronomy.


Riess was a Miller Fellow at the University of California, Berkeley, before moving on to the Space Telescope Science Institute in 1999. He took up his current position at Johns Hopkins University in 2006. He also sits on the selection committee for the Astronomy award, given under the auspices of the Shaw Prize. In July 2016, Riess was named a Bloomberg Distinguished Professor at Johns Hopkins University for his accomplishments as an interdisciplinary researcher and excellence in teaching the next generation of scholars. The Bloomberg Distinguished Professorships were established in 2013 by a gift from Michael Bloomberg. 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 groundbreaking work. Riess leads the Higher-Z SN Search program which uses the Hubble Space Telescope to discover the most distant supernovae yet seen by humankind. His team has traced the Universe's expansion back more than 10 billion light years. The key finding has been the detection of an early phase of decelerating expansion causing the most distant supernovae to look relatively brighter and thus disfavoring significant astrophysical dimming of supernovae. This result thus confirms the dark energy-dark matter model as perceived from supernovae. The Calan-Tololo project made significant contributions to the measurement of distances in the Universe, contributing to the discovery in 1998 of the acceleration of the expansion of the Universe. This discovery was made by two international scientific teams: The High-Z SN Search Team and the Supernova Cosmology Project. As a result of this discovery, on October 4, 2011 astronomers Saul Perlmutter, Brian P. Schmidt and Adam Riess were awarded the Nobel Prize in Physics. The Royal Swedish Academy of Sciences (entity that awards the Nobel Prize), made an explicit recognition to the Calan Tololo project, in its ""scientific background".The Calan Tololo project was recognized by the Royal Swedish Academy of Sciences, on October 2011 -in its document Scientific Background on the Nobel Prize in Physics 2011-, due to its essential contribution to the Discovery of the Acceleration of the Expansion of the Universe. The text highlights on page 11: "In parallel, light curves of several nearby type Ia supernovae were being measured in the course of the Calan/Tololo Supernova Survey project led by Chilean astronomer Mario Hamuy, Mark Phillips, Nicholas Suntzeff of the Cerro Tololo Inter-American Observatory in Chile and José Maza of the University of Chile. These data were essential to demonstrate that type Ia supernovae were useful as light patterns. This breakthrough was made possible by using a relationship between maximum luminosity and decay time, demonstrated by Mark Phillips, to recalibrate type Ia supernovae to a standard profile". Some of the consequences of the observation of type I-a supernovae are The Universe is accelerating and the expansion will continue forever. Half of the experiment was done in Chile, by Chilean and American astronomers; without the Calan/Tololo data this discovery of acceleration would not have been possible. There is a type of "repulsive" force in nature whose origin remains unknown. The supernova experiment produced a revolution in contemporary astrophysics. The amount of energy associated with this force constitutes 70% of all the energy in the Universe and is called dark energy. In the book The 4 Percent Universe, scientific journalist Richard Panek claims that Riess made improper use of the supernova data collected by the Calán/Tololo Survey, publishing them prior to the authors and without their permission. However, coincident publication dates and acknowledgements in one of these publications contradict this claim.

Awards and honors

Saul Perlmutter, Riess, and Brian P. Schmidt being awarded the 2006 Shaw Prize in Astronomy. The trio would later be awarded the 2011 Nobel Prize in Physics. Riess received the Astronomical Society of the Pacific's Robert J. Trumpler Award in 1999 and Harvard University's Bok Prize in 2001. He won the American Astronomical Society's Helen B. Warner Prize in 2003 and the Raymond and Beverly Sackler Prize in 2004 for the discovery of cosmic acceleration. In 2006, he shared the $1 million Shaw Prize in Astronomy with Saul Perlmutter and Brian P. Schmidt for contributions to the discovery of the acceleration of the universe. Schmidt and all the members of the High-Z Team (as defined by the co-authors of Riess et al. 1998) shared the 2007 Gruber Cosmology Prize, a $500,000 award, with the Supernova Cosmology Project (the set defined by the co-authors of Perlmutter et al. 1999) for their discovery of the accelerating expansion of the universe. Riess was the winner of MacArthur "Genius" Grant in 2008. He was also elected in 2009 to the National Academy of Sciences. Along with Perlmutter and Schmidt, he was awarded the 2011 Nobel Prize in Physics for his contributions to the discovery of the acceleration of the expansion of the universe. Riess, along with Brian P. Schmidt, and the High-Z Supernova Search Team shared in the 2015 Breakthrough Prize in Fundamental Physics. In 2020, Riess was made fellow of the American Astronomical Society.

Media appearances

Riess participated on the NPR radio quiz program Wait Wait… Don't Tell Me! in 2011.


Questions have also been raised about the statistical methodology of the team.

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