Simulating the Multiverse With the Grid

Cristiano Sabiu from the University of Portsmouth is using the U.K’s NGS Grid to look at two unsolved issues in cosmology. The first question is: what is causing the universe to expand at an accelerated rate? This unknown force is usually called dark energy. The second has to do with observations that an extra source of gravity must exist in the universe. It is thought that there are particles which do not emit light and only interact through the gravitational force. This is usually called dark matter.

Sabiu’s research focuses on exploring how the galaxies we see are connected to this invisible dark matter. This required running many large scale N-body simulations of dark matter. From these simulations he created a multiverse of almost 2000 mock universes which explored multiple HOD models. These were then compared to the actual galaxy distribution as observed by the Sloan Digital Sky Survey (SDSS) allowing the placing of tight constraints on the model parameters. The simulations were run using the publicly available GADGET2 code. GADGET2 is an N-body integration routine which can run cosmological simulations on massively parallel computers with distributed memory. GADGET2 uses an explicit communication model that is implemented with the standardised MPI communication interface. The code can be run on essentially all supercomputer systems presently in use, including clusters of workstations or individual PCs.

Read the Full Story.

I find myself reading more and more about cosmology these days. If this is your kind of thing, check out Dr. Stephen Perrenod’s new book, Dark Matter, Dark Energy, Dark Gravity: Enabling a Universe that Supports Intelligent Life. I was fortunate enough to have contributed the Foreword for this book, and Steve does a great job of explaining these complex ideas in layman’s terms.