This animation shows a model of the web-like structure of dark matter. The area covered is 1 billion times 1 billion light-years, and reaches billions of light-years in depth.

Matter, including the dark matter that we can’t see, is not evenly distributed throughout the huge expanses of intergalactic space, but arranged in filamentary structures often referred to as the cosmic web. The presence of dark matter enhances the gravitational pulls and the formation of this network.

The shape and distribution of galaxies that Euclid observes are affected by the ‘geography’ of the dark matter. Euclid’s extremely accurate and precise measurements of large areas of the night sky can be used to infer this distribution, and how it has changed over time.

This change over time in dark matter, and the clustering in its overall spatial distribution, also reveals the role and properties of dark energy.