D. O. Gough, A. G. Kosovichev, J. Toomre, E. Anderson, H. M. Antia, S. Basu, B. Chaboyer, S. M. Chitre, J. Christensen-Dalsgaard, W. A. Dziembowski, A. Eff-Darwich, J. R. Elliott, P. M. Giles, P. R. Goode, J. A. Guzik, J. W. Harvey, F. Hill, J. W. Leibacher, M. J. P. F. G. Monteiro, O. Richard, T. Sekii, H. Shibahashi, M. Takata, M. J. Thompson, S. Vauclair, S. V. Vorontsov

Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics.

D. O. Gough, J. R. Elliott, and T. Sekii are with the Institute of Astronomy, University of Cambridge, CB3 0HA, UK. A. G. Kosovichev and P. R. Giles are with HEPL, Stanford University, Stanford, CA, USA. J. Toomre is at JILA, University of Colorado, Boulder, CO, USA. E. Anderson, J. W. Harvey, F. Hill, and J. W. Leibacher are at the National Solar Observatory, Tucson, AZ, USA. H. M. Antia and S. M. Chitre are at the Tata Institute for Fundamental Research, Bombay, India. S. Basu and J. Christensen-Dalsgaard are at the Theoretical Astrophysics Centre, Aarhus University, Denmark. B. Chaboyer is at the Canadian Institute for Theoretical Astrophysics, Toronto, Canada. W. A. Dziembowski is at the Copernicus Astronomical Center, Warsaw, Poland. A. Eff-Darwich is at the Instituto Astrofisico de Canarias, Tenerife, Canary Islands. P. R. Goode is at the New Jersey Institute of Technology, Newark, NJ, USA. J. A. Guzik is at the Los Alamos National Laboratory, Los Alamos, NM, USA. M. J. P. F. G. Monteiro is at the University of Oporto, Portugal. O. Richard and S. Vauclair are at the Observatoire Midi-Pyrenees, Toulouse, France. H. Shibahashi and M. Takata are in the Department of Astronomy, University of Tokyo, Tokyo, Japan. M. J. Thompson and S. V. Vorontsov are at Queen Mary and Westfield College, University of London, London, UK.