Computer simulations have reached a quality that now makes simulation based sciences and engineering an equal partner in natural sciences along with theory and experimentation. The field is vast and by no means limited to the traditional disciplines of computational physics (e.g. quantum chromodynamics, astrophysics, and cosmology) and engineering (fluid dynamics and continuum mechanics).
With ever increasing computer performance, climate and weather simulations are reaching scales where they become predictive and are thereby directly impacting the political and economic decision processes; simulations in nano-, materials, and chemical sciences can now be compared quantitatively with experiments and thus allow studies of systems and scales that are difficult or too expensive to access experimentally; in neurobiology, modeling of brain functions is reaching unprecedented levels of sophistication at the level of the cervical column; high-fidelity combustion simulations enable understanding and optimization of the efficiency of engines; and simulations in plasma physics now play a key role in designing fusion reactors.
These and many other examples have been enabled by the transformational changes that have occurred in computer hardware during this first decade of the new millennium.