Sten Delos is a CTAC postdoctoral fellow interested in small-scale cosmic structure and how it can inform us about fundamental physics. Focusing primarily on subgalactic scales, he uses numerical simulations and mathematical arguments to understand how the distribution of the dark matter is set by the particle nature of the dark matter and the physics of the early universe. He also thinks about ways to detect the gravitational influence of systems of dark matter that are too small to contain any stars.