Steven Andrew Balbus (born 23 November 1953) is an American astrophysicist who is the
Savilian Professor of Astronomy
The position of Savilian Professor of Astronomy was established at the University of Oxford in 1619. It was founded (at the same time as the Savilian Professorship of Geometry) by Sir Henry Savile, a mathematician and classical scholar who was ...
Emeritus at the
University of Oxford
The University of Oxford is a collegiate university, collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the List of oldest un ...
and a senior research fellow at
New College, Oxford
New College is a constituent college of the University of Oxford in the United Kingdom. Founded in 1379 by Bishop William of Wykeham in conjunction with Winchester College as New College's feeder school, New College was one of the first col ...
. In 2013, he shared the
Shaw Prize
The Shaw Prize is a set of three annual awards presented by the Shaw Prize Foundation in the fields of astronomy, medicine and life sciences, and mathematical sciences. Established in 2002 in Hong Kong, by Hong Kong entertainment mogul and p ...
Philadelphia, Pennsylvania
Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...
. He attended the
William Penn Charter School
William Penn Charter School (commonly known as Penn Charter or simply PC) is an elite private school in Philadelphia, Pennsylvania. It was founded in 1689 at the urging of William Penn as the "Public Grammar School" and chartered in 1689 to b ...
, received S.B. degrees in mathematics and
in physics from the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
(MIT) in 1975, and a PhD in theoretical
astrophysics
Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the ...
from the
University of California, Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...
in 1981.
Research and career
Following his PhD, Balbus held
postdoctoral research
A postdoctoral fellow, postdoctoral researcher, or simply postdoc, is a person professionally conducting research after the completion of their doctoral studies (typically a PhD). Postdocs most commonly, but not always, have a temporary acade ...
appointments at MIT and
Princeton University
Princeton University is a private university, private Ivy League research university in Princeton, New Jersey, United States. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial ...
. In 1985, Balbus joined the faculty of the
University of Virginia
The University of Virginia (UVA) is a Public university#United States, public research university in Charlottesville, Virginia, United States. It was founded in 1819 by Thomas Jefferson and contains his The Lawn, Academical Village, a World H ...
de Paris. He remained
in Paris until 2012, when he moved to Oxford as the
Savilian Professor of Astronomy
The position of Savilian Professor of Astronomy was established at the University of Oxford in 1619. It was founded (at the same time as the Savilian Professorship of Geometry) by Sir Henry Savile, a mathematician and classical scholar who was ...
. He retired from this post in October 2024, retaining Emeritus status. At Oxford, he taught astrophysical
gas dynamics
Compressible flow (or gas dynamics) is the branch of fluid mechanics that deals with flows having significant changes in fluid density. While all flows are compressible, flows are usually treated as being incompressible when the Mach number (the ...
, general relativity, and supervised postdoctoral researchers and students.
Balbus' research is in theoretical astrophysics. He has made discoveries related to gravitational instability in the interstellar medium and several contributions to the theory of thermal processes in magnetised dilute plasmas. He is best known for a 1991 paper, published with former colleague John F. Hawley, describing what is now known as magnetorotational instability (MRI). Most recently, Balbus has been working on a theory of the Sun's internal rotation. As of 2016, Balbus has also been lecturing an undergraduate course in general relativity at the University of Oxford; with several lectures coinciding with the discovery of
gravitational wave
Gravitational waves are oscillations of the gravitational field that Wave propagation, travel through space at the speed of light; they are generated by the relative motion of gravity, gravitating masses. They were proposed by Oliver Heaviside i ...
s in February 2016.
Awards and honours
Balbus was awarded a Chaire d'excellence in 2004 by the French Ministry of Higher Education. In 2013, he shared the
Shaw Prize
The Shaw Prize is a set of three annual awards presented by the Shaw Prize Foundation in the fields of astronomy, medicine and life sciences, and mathematical sciences. Established in 2002 in Hong Kong, by Hong Kong entertainment mogul and p ...
in Astronomy with Hawley for their work on the MRI. Considered one of the highest honours in astronomy, the prize included a US$1 million cash award. According to the Shaw selection committee the "discovery and elucidation of the magnetorotational instability (MRI)" solved the previously "elusive" problem of accretion, a widespread phenomenon in astrophysics and "provides what to this day remains the only viable mechanism for the outward transfer of angular momentum in accretion disks".
Balbus is the recipient of a
Royal Society Wolfson Research Merit Award
The Royal Society Wolfson Fellowship, known as the Royal Society Wolfson Research Merit Award until 2020, is a 5 years fellowship awarded by the Royal Society since 2000. The scheme is described by the Royal Society as providing ''long-term flexib ...
, and has held visiting faculty positions at Princeton University ( Bohdan Paczynski Visitor and Spitzer Lecturer, 2011) and the University of California, Berkeley (Visiting Miller Professor, 2012). In April 2015, Balbus was elected to the US
National Academy of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...
. He was elected a Fellow of the Royal Society (FRS) in 2016. One or more of the preceding sentences incorporates text from the royalsociety.org website where: In 2020 he was awarded the
Eddington Medal
The Eddington Medal is awarded by the Royal Astronomical Society for investigations of outstanding merit in theoretical astrophysics. It is named after Sir Arthur Eddington. First awarded in 1953, the frequency of the prize has varied over the ye ...
of the
Royal Astronomical Society
The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its ...
Institute of Physics
The Institute of Physics (IOP) is a UK-based not-for-profit learned society and professional body that works to advance physics education, physics research, research and applied physics, application.
It was founded in 1874 and has a worldwide ...
. In 2023 he was awarded the Nick Kylafis Lectureship