Dark matter has long been a subject of speculations, even though scientists know that its existence makes sense. The biggest challenge is to locate places in the Universe where it is hiding, as dark matter is invisible. However, it can be seen indirectly by observing its effect on surrounding stars and galaxies. Dark matter’s gravity tugs on light that passes through it, bending it in a phenomenon called gravitational lensing. Thanks to this, a team of researchers created a 3D map of dark matter, which shows places in the Universe where such lensing appears.
The map can help us understand dark energy
The map, which was published in the preprint journal arXiv on Monday, is expected to be very helpful in explaining the way dark energy behaves in space. According to Rachel Mandelbaum, a member of the team and astronomer at Carnegie Mellon University in Pittsburgh, this map can shed more light on the properties of dark energy and the expansion of the Universe which is driven by this force.
How was the map built
In order to create the map, the scientists studied the shapes of almost 10 million galaxies, those close to Earth and those that are very far away from us, and whose light is reaching us after billions of years. Once they gathered enough data, the researchers looked closely at those distortions in the shapes of galaxies that were a result of dark matter lensing, which allowed them to measure the amount of dark matter that the light has to go through on its way to Earth.
The images, upon which the map was built, where taken by the Japanese Subaru Telescope, located in Hawaii. The study is part of a project named Hyper Suprime-Cam survey (HSC), which will continue monitoring the Universe for the next four years in order to make the map even more precise.