has shaped the science investment in the United States and elsewhere around the world. Turner is currently the chair of the Physics Section of the National Academy of Sciences and the chair-elect of the Division of Astrophysics within the American Physical Society.

J. ANTHONY (TONY) TYSON is Distinguished Professor of Physics at the University of California at Davis and the director of the Large Synoptic Survey Telescope (LSST). LSST will look wide, fast, and deep, scanning the entire night sky every three nights for 10 years. Its mission will be to map the mysterious “dark matter” and “dark energy” that physicists say make up 95 percent of the universe. His research interests are in cosmology, dark matter, dark energy, observational optical astronomy, experimental gravitational physics, and new instrumentation. He received his Ph.D. from University of Wisconsin in 1967 and was a member of the technical staff at Bell Laboratories from 1969 to 2003. His honors include election to the American Philosophical Society and the National Academy of Sciences, the Aaronson Memorial Prize, and fellowships in the American Academy of Arts and Sciences and the American Physical Society.

STEVEN C. WOFSY is the Abbott Lawrence Rotch Professor of Atmospheric and Environmental Sciences in the Department of Earth and Planetary Sciences at Harvard University. Dr. Wofsy holds a Ph.D. in chemistry from Harvard University. He studies a variety of atmospheric gases using instruments aboard aircraft and also on the ground at long-term measurement sites. His research interests include undertaking theoretical and modeling studies to understand depletion of stratospheric ozone in polar regions, to assess future impacts of pollutants injected into the stratosphere, and to examine ecological and historical factors affecting atmospheric concentrations of CO₂. In 2001, Dr. Wofsy received the Distinguished Public Service Medal from the National Aeronautics and Space Administration. He is a fellow of the American Geophysical Union and the American Association for the Advancement of Science.