Dark matter is leading a small galaxy to collide with our milky way, indicates a new map of the outer regions of our galaxy released by astronomers. The all-sky map which uses data from NASA and the European space agency(ESA) reveals how the Large Magnetic Cloud, a small galaxy that is 160,000 light-years away from earth, is set on its course to the collision that will happen in about 2 billion years. The collision will be caused by the ocean of dark matter that is present in our Milky Way’s galactic halo, the outer regions of a galaxy. The massive gravitational pull of the dark matter will dwarf the small galaxy’s orbit, dragging and slowing it down leading to the merger.
Dark matter exists five times more than all the visible matter in the universe. And it is not just the galactic halo where it exists. Dark matter permeates through everything. It is what keeps the stars and galaxy in their position, like leaves on the surface of a sea. There is dark matter in the room where you are reading this article. No intensity of light can see it as it does not react to it, giving it its name. We can only feel its gravitational pull as it always shows up in our calculations, which can be used to build predictive models of how dark matter affects the visible universe. For example, scientists’ prediction of the small galaxy’s movement also accounts for dark matter.
“Confirming our theoretical prediction with observational data tells us that our understanding of the interaction between these two galaxies, including the dark matter, is on the right track,” said Nicolás Garavito-Camargo, who led the research. Garavito-Camargo is a doctoral student of astronomy at the University of Arizona.
Astronomers can use the new map to test their dark matter theories, a rare opportunity to study the properties of dark matter present in our milky way. The paper was published in Nature by a group of seven scientists on April 21.