Researchers have developed a novel computer simulation of dark matter that offers information on the density profiles of the bubble-like cosmic voids that exist within this elusive substance. They found that these voids not only come in various shapes and sizes, but also that the density is greatest around the void boundaries. The study has been published in Physical Review Letters.
It is estimated that around 27% of the universe is comprised of dark matter- the rest is dark energy and normal matter. While we know this much, what precisely dark matter is is a different kettle of fish entirely. Scientists have a long list of what dark matter is not, but struggle to define what it is made up of, making it a subject of great interest amongst astronomers.
In order to further our knowledge of this mysterious substance, researchers have been running computer simulations based on observations so far. This work has led scientists to believe that dark matter probably has a honeycomb-like architecture with various pockets of space surrounded by material. It is predicted that these so-called cosmic voids form when dark matter collapses under its own gravity, producing stringy filaments that eventually create a border around the newly-formed voids. Models have also suggested that the void takes up a larger proportion of dark matter than the boundaries.
In this latest study, the researchers generated a new simulation in order to gain a better understanding of the density profiles of cosmic voids. Like others before, they found that voids come in various morphologies and sizes. However, they also discovered that the density of dark matter was greatest within the void boundaries. Lastly, previous work has led to the prediction that the centers of voids are home to spherical densities; they found this to be a universal feature and was true no matter the shape or size of the void, and also for voids that existed earlier in the timeline of the universe.