Computer simulations are ubiquitous in science and engineering. In physics and chemistry, we have simulations of atoms and molecules. In biology, we have simulations of cells and organisms. In neuroscience, we have simulations of neural networks. In engineering, we have simulations of cars, planes, bridges, and buildings. In planetary science, we have simulations of Earth’s climate over many decades. In cosmology, we have simulations of the known universe as a whole.