A numerical approach to binary black hole coalescence
  The nature of binary black hole coalescence is the final, uncharted frontier of the relativistic Kepler problem. In the United States, binary black hole coalescence has been identified as a computational ``Grand Challenge'' whose solution is the object of a coordinated effort, just reaching its half-way point, by more than two-score researchers at nearly a dozen institutions. In this report I highlight what I see as the most serious problems standing between us and a general computational solution to the problem of binary black hole coalescence:   * the computational burden associated of the problem based on reasonable extrapolations of present-day computing algorithms and near-term hardware developments;   * some of the computational issues associated with those estimates, and how, through the use of different or more sophisticated computational algorithms we might reduce the expected burden; and   * some of the physical problems associated with the development of a numerical solution of the field equations for a binary black hole system, with particular attention to work going on in, or in association with, the Grand Challenge. 
Lee Samuel Finn (Physics and Astronomy Department, Northwestern   University)