While we still know very little about dark matter – other than that we can’t feel it or see it, though it accounts for 27% of all matter and energy – a new study shows that the relationship between the mysterious cosmic energy and galaxies is a lot more complex than we first thought.
Scientists have so far discovered that the denser a galaxy cluster (which is typically made up of hundreds of thousands of galaxies that are bound together by gravity), the more dark matter it has in the surrounding environment.
To place us in the universe, Earth and the Milky Way galaxy sits in the Virgo or Local Supercluster.
The new study, published today in Physical Review Letters and led by Hironao Miyatake, shows that the surrounding dark matter environment not only effects how heavy a cluster might be, but also, for the first time, that it also effects the location of the clusters as well, according to NASA.
The researchers studied approximately 9,000 galaxy clusters, dividing them into two groups: densely packed clusters and clusters in which galaxies were more spread out.
Normally, galaxy clusters are separated from each other by about 100 million light-years, but by comparing the two types of clusters, researchers found that denser clusters had fewer neighbors at this distance than the less packed ones.
“This difference is a result of the different dark-matter environments in which the groups of clusters formed,” Miyatake said. “Our results indicate that the connection between a galaxy cluster and surrounding dark matter is not characterized solely by cluster mass, but also its formation history.”