Historically, studies of specific problems and corresponding breakthroughs have led to new scientific disciplines. Physics, Chemistry and Astronomy emerged out of Natural Philosophy following the important discoveries by Newton, LaVoisier and Galileo respectively. The type of problems in which computational science could achieve breakthroughs are generally referred to as 'grand challenges'. A nice definition of grand challenges stems from the Office of Science and Technology Policy:
Grand Challenges are...fundamental problems in science and engineering, with potentially broad social, political, and scientific impact, that could be advanced by applying high performance computing resources.As expected, there is a long list of grand challenge problems, including electronic structure of materials, turbulence, genome sequencing and structural biology, global climate modeling, speech and language studies, pharmaceutical design, pollution and dispersion, and many more. The grand challenges supported by the government under the High Performance Computing and Communications initiative are a select set of these.