John E. Carlstrom was born in in 1957 in Hyde Park, New York. He earned his A. B. in physics at Vassar College in 1981 and his Ph.D. in physics at the University of California, Berkeley, in 1988. After a brief stay at Berkeley as an Assistant Astronomer, he moved to Caltech where he was initially a Millikan Postdoctoral Fellow and then in 1991 became a member of the faculty. In 1995 he joined the faculty at the University of Chicago. There he has served as the director of the Center for Astrophysical Research in Antarctica and the Kavli Institute for Cosmological Physics. Among the current positions he holds are the Subramanyam Chandrasekhar Distinguished Service Professor at U. Chicago and the director of the South Pole Telescope.
It is largely for this latter role that he is receiving a Gruber Cosmology Prize. Carlstrom has worked extensively in the study of the cosmic microwave background (or CMB, the relic radiation from the infancy of the universe that contains the imprint of everything the universe would become), including leading the Degree Angular Scale Interferometer, also at the South Pole. Like the Atacama Cosmological Telescope, overseen by his co-Gruber recipient Lyman Page, the SPT has made precise measurements of the CMB that, among other things, led to the discovery of hundreds of clusters of galaxies going back to when the universe was about one-third its present age, providing a history of the growth of the large-scale structure of the universe. The SPT measurements provide independent verification that the universe consists of approximately 25 percent dark matter, 70 percent dark energy, and 5 percent atoms; and strong evidence that the structure in the CMB is a remnant of quantum fluctuations. This latter data is in excellent agreement with inflation, a theory in which all the cosmic structure we observe—stars, galaxies, clusters of galaxies—arose from quantum fluctuations.
Carlstrom received a John D. and Catherine T. MacArthur Fellowship in 1998, the Magellanic Premium Medal of the American Philosophical Society in 2005, and the Beatrice M. Tinsley Prize of the American Astronomical Society in 2006, among many other honors. He has been a member of the American Academy of Arts and Sciences since 2000, a member of the National Academy of Sciences since 2002.