CPU Study to Set Research Priorities at Interface of Physics, Astronomy

Members of the Committee on Physics of the Universe Michael Turner, University of Chicago (chair) Roger D. Blandford, Caltech Sandra M. Faber, University of California, Santa Cruz Thomas K. Gaisser, University of Delaware Fiona Harrison, Caltech John P. Huchra, Harvard University Helen R. Quinn, Stanford Linear Accelerator Center R.G. Hamish Robertson, University of Washington Bernard Sadoulet, University of California, Berkeley Frank J. Sciulli, Columbia University David N. Spergel, Princeton University J. Anthony Tyson, Lucent Technologies Frank A. Wilczek, MIT Clifford Will, Washington University Bruce D. Winstein, University of Chicago

In the week just prior to the APS April Meeting in Long Beach, California, the Sloan Digital Sky survey found the most distant object in the universe, believed to be a quasar - an object 27 billion light years away in a universe that is only 14 billion light years old, making it an excellent teaching tool on the expanding universe as well as a significant scientific advance. That same week, the Boomerang Project, operated jointly by the NSF, NASA and the DOE, produced the first time-resolution maps of the cosmic background radiation, providing strong evidence for the prevailing cosmological theory that the universe is flat. Both recent announcements are excellent examples of the exciting research taking pace at the intersection of physics and astronomy, said Michael Turner (University of Chicago) in a talk given at a special session of the April Meeting. He is the chair of the National Academy of Science's Committee on the Physics of the Universe (CPU). Jointly funded by the NSF, the DOE and NASA, the committee is charged with assessing the area of science between the two fields, providing a broad vision extending beyond traditional categories of space missions, laboratory studies, telescope observations and accelerator experiments. Specifically, it will address opportunities to explore new science through new techniques for observing phenomena in extreme environments and new regimes; new applications of fundamental physics to modeling and simulating the origin, evolution and fate of the universe; and understanding fundamental physics by using space and the cosmos as a laboratory full of experiments that could never be implemented on Earth.

"One of the problems of this field is that many of the research directions are of secondary interest in the context purely of either physics or astronomy," says Turner of the need for such a study. "But in a context that includes the interest of both fields, many of the issues are among the most profound and far reaching questions that science can address."

Among the broad-ranging topics to be covered are strong-field gravitational physics; the origin of high-energy cosmic rays; neutrino observations and their implications for the nature of supernovae and the dynamics of the Sun; black holes; and the condition of the universe moments after the Big Bang. "These phenomena provide unique cosmic experiments probing the laws of physics in regimes that are not accessible on Earth," says Turner. "Conversely, understanding these phenomena challenges our abilities to apply the laws of physics in new regimes."

Entitled "From Quarks to the Cosmos," the CPU study will cover the most fundamental aspects of cosmology, and will consist of two phases. Phase I, to be completed by the end of the year, will identify the scientific priorities of the field, drawing on the combined expertise of the distinguished committee members as well as input from the scientific community. Phase II of the study will focus on the more difficult task of setting priorities for the development of this emerging new interdisciplinary field, and devise mechanisms for evaluating future opportunities and fostering cooperation among the three agencies sponsoring the study. The entire 200-page final report is expected to be completed in January 2002.

"This study will, for the first time, examine and evaluate this fundamentally interdisciplinary science on its own merits and in a broad context encompassing both physics and astronomy," Turner says. "A common picture of how the various aspects of the field fit together will enable a smoother planning process, as well as better communication in the research community, while setting priorities will facilitate action on key requirements to realize the new opportunities outlined in the survey."

Community input is critical to the success of such a venture. Turner gave a similar presentation at the American Astronomical Society meeting last month to further foster awareness of the CPU study among physicists and astronomers, along with the first draft of the report. A third presentation is scheduled at the APS Division of Particles and Fields meeting at Ohio State University in August to solicit initial community input. Once the Phase I report is complete, formal public input on ideas and mission concepts will be sought through a series of fora, the first of which will be held at the AAS meeting in San Diego in January 2001.

The APS meeting in Washington in April 2001 will have sessions devoted to discussions of these issues as well.