How to represent on a map something that we cannot see? This is the question astronomers ask themselves when studying the dark matter in the Universe. This matter does not emit light or enough electromagnetic radiation to be detected with our technical means, however we can know it through its effects on visible matter.
Dark matter is thought to occupy 23 percent of the mass of the Universe, and although we cannot see or touch it, we know that it exists because it influences the formation and rotation speed of galaxies. In order to analyze this elusive element, scientists take advantage of the small distortions that dark matter causes in the shapes of galaxies using what is called the "gravitational lensing" effect. With this technique, a group of astronomers from the universities of British Columbia and Edinburgh have calculated the distribution of dark matter in a region of more than one billion light years, creating the first "dark" map of the Universe.
This invisible matter is concentrated in large masses and filaments that form a network in whose knots, coinciding with galaxy clusters, a greater amount of dark matter would be concentrated. Many of these galaxies are six billion light-years away, which means that the light seen in the map images was emitted by them six billion years ago, when the age of the Universe was half that of today.
