Sean Michael Carroll (/ˈkærəl/; born October 5, 1966) is a cosmologist and physics professor specializing in dark energy and general relativity. He is a research professor in the Department of Physics at the California Institute of Technology. He has been a contributor to the physics blog Cosmic Variance, and has published in scientific journals and magazines such as Nature, The New York Times, Sky & Telescope, and New Scientist.
He has appeared on the History Channel's The Universe, Science Channel's Through the Wormhole with Morgan Freeman, Closer to Truth (broadcast on PBS), and Comedy Central's The Colbert Report. Carroll is the author of Spacetime And Geometry, a graduate-level textbook in general relativity, and has also recorded lectures for The Great Courses on cosmology, the physics of time, and the Higgs boson. He is also the author of three popular books: one on the arrow of time entitled From Eternity to Here, one on the Higgs boson entitled The Particle at the End of the Universe, and one on science and philosophy entitled The Big Picture: On the Origins of Life, Meaning, and the Universe Itself.
Carroll received his PhD in astronomy and astrophysics in 1993 from Harvard University, where his advisor was George B. Field. His dissertation's title is "Cosmological Consequences of Topological and Geometric Phenomena in Field Theories". He worked as a postdoctoral researcher at the Massachusetts Institute of Technology and Kavli Institute for Theoretical Physics at the University of California, Santa Barbara, and as an assistant professor at the University of Chicago until 2006 when he was denied tenure. He is now a research professor at Caltech.
His most-cited work, "Is Cosmic Speed-Up Due To New Gravitational Physics?", was written with Vikram Duvvuri, Mark Trodden, and Michael Turner. With over 1,900 citations, it helped pioneer the study of f(R) gravity in cosmology.
In 2010, Carroll was elected as a fellow of the American Physical Society, for "contributions to a wide variety of subjects in cosmology, relativity, and quantum field theory, especially ideas for cosmic acceleration, as well as contributions to undergraduate, graduate, and public science education". In 2014 he was awarded the Andrew Gemant Award, a prize given by the American Institute of Physics for "significant contributions to the cultural, artistic or humanistic dimension of physics." In 2015 he was awarded a Guggenheim Fellowship.
Carroll has worked on a number of topics in theoretical cosmology, field theory, and gravitation theory. His research papers include models of, and experimental constraints on, violations of Lorentz invariance; the appearance of closed timelike curves in general relativity; varieties of topological defects in field theory; and cosmological dynamics of extra spacetime dimensions. In recent years he has written extensively on models of dark energy and its interactions with ordinary matter and dark matter, as well as modifications of general relativity in cosmology.
Carroll has also worked on the arrow of time problem. He and Jennifer Chen posit that the Big Bang is not a unique occurrence as a result of all of the matter and energy in the universe originating in a singularity at the beginning of time, but rather one of many cosmic inflation events resulting from quantum fluctuations of vacuum energy in a cold De Sitter space. Carroll and Chen claim that the universe is infinitely old, but never reaches thermodynamic equilibrium as entropy increases continuously without limit due to the decreasing matter and energy density attributable to recurrent cosmic inflation. They assert that the universe is "statistically time-symmetric" insofar as it contains equal progressions of time "both forward and backward". Some of his work has been on violations of fundamental symmetries, the physics of dark energy, modifications of general relativity, and the arrow of time. Recently he started focusing on issues at the foundations of cosmology, statistical mechanics, quantum mechanics, and complexity.
Views on religion
Carroll is an atheist, or as he calls it, a "poetic naturalist". He turned down an invitation to speak at a conference sponsored by the John Templeton Foundation, on the grounds that he did not want to appear to be supporting a reconciliation between science and religion; however, he later took part in a discussion with Buddhist scholar B. Alan Wallace organized by an institution sponsored by the same foundation. In 2004, he and Shadi Bartsch taught an undergraduate course title at the University of Chicago on the history of atheism. In 2012 he organized the workshop "Moving Naturalism Forward", which brought together scientists and philosophers to discuss issues associated with a naturalistic worldview. His article, "Does the Universe Need God?" in The Blackwell Companion to Science and Christianity develops the claim that science no longer needs to posit a divine being to explain the existence of the universe. The article generated significant attention when it was discussed on The Huffington Post. His 2016 book The Big Picture: On the Origins of Life, Meaning and the Universe Itself develops the philosophy of poetic naturalism.
Carroll occasionally takes part in formal debates or discussions with theists. In 2012, Carroll teamed up with Michael Shermer to debate with Ian Hutchinson of MIT and author Dinesh D'Souza at Caltech in an event titled "The Great Debate: Has Science Refuted Religion?" In 2014, Carroll debated with philosopher and Christian apologist William Lane Craig as part of the Greer-Heard Forum in New Orleans. The topic for the debate was "The Existence of God in Light of Contemporary Cosmology." Carroll received an "Emperor Has No Clothes" award at the Freedom From Religion Foundation Annual National Convention in October 2014.
- Carroll, Sean (2003). Spacetime and Geometry: An Introduction to General Relativity. ISBN 0-8053-8732-3.
- Carroll, Sean (2010). From Eternity To Here: The Quest for the Ultimate Theory of Time. ISBN 0-525-95133-4. It tackles a fundamental open principle in physics: the arrow of time.
- Carroll, Sean (2012). The Particle at the End of the Universe: How the Hunt for the Higgs Boson Leads Us to the Edge of a New World. ISBN 0-525-95359-0. It describes the hunt for and discovery of the Higgs boson at the Large Hadron Collider at CERN and was the 2013 winner of the Royal Society Winton Prize for Science Books.
- Carroll, Sean (2016). The Big Picture: On the Origins of Life, Meaning, and the Universe Itself. ISBN 0-5259-5482-1., where Carroll introduces the concept of poetic naturalism.
- , from the INSPIRE-HEP digital library.