The Orren C. Mohler Prize Lecture

"Simulated Universes: Origin and Fate of Our Milky Way"

Galaxies contain hundreds of billions of stars and display a wide variety of shapes and sizes. But these cosmic lighthouses are just markers for even much vaster structures lying underneath. In fact, astrophysicists are convinced that the vast majority of the energy and matter content of the Universe does not consist of ordinary matter, but is dominated by enigmatic dark matter and dark energy components. Supercomputer simulations play a crucial role in testing this seemingly daring cosmological hypothesis. The astonishing performance of today's supercomputers makes it possible to link the relatively simple initial conditions left by the Big Bang directly with the complex, developed state of the present universe and thus trace the life of galaxies in detail. They show how a cosmic network of dark matter is created over 13 billion years, at the intersections of which structures of various sizes form, from small dwarf galaxies to enormous galaxy clusters. The supercomputers also make predictions about the specific formation history of the Milky Way, and how it should develop in the future. At the same time, the simulations can also help us to explain extreme phenomena such as the effect of supermassive black holes on the cosmic evolution of galaxies.