The Universe hides a gigantic structure invisible to the naked eye. Galaxies organize themselves into a network called the cosmic web.
This cosmic web, the largest known natural structure, connects galaxies through filaments of dark matter. These filaments stretch across tens of millions of light-years, creating immense walls that divide the Universe into vast regions. Computer simulations reveal that this structure influences the distribution of all cosmic matter.
Simulation of the cosmic web.
Credit: F. Vazza, D. Wittor et J. West
Between these filaments lie nearly empty spaces, the cosmic voids. These regions, spanning hundreds of millions of light-years, contain very little visible matter. Yet, they are not completely deserted, hosting a few dwarf galaxies and traces of dark matter.
Dark matter, invisible, forms the scaffolding of the cosmic web. Although less dense in the voids, it traces faint filaments there.
In cosmic voids, dark energy dominates. Representing 70% of the Universe's energy, it accelerates its expansion. These regions, nearly devoid of matter, are the main stage for this still poorly understood force.
The study of cosmic voids and the cosmic web helps us better understand the evolution of the Universe. This research highlights the importance of simulations and observations to unravel the mysteries of the cosmos.
What is dark matter?
Dark matter is a form of invisible matter that neither emits nor absorbs light. It makes up about 27% of the Universe, but its exact nature remains unknown.
Scientists detect dark matter indirectly through its gravitational influence on galaxies and galaxy clusters. Without it, galaxies could not maintain their current structure.
Current research attempts to determine whether dark matter consists of exotic particles. These studies could revolutionize our understanding of fundamental physics.
Despite its invisibility, dark matter plays a crucial role in the formation and evolution of cosmic structures, such as the cosmic web.
How does dark energy influence the Universe?
Dark energy is a mysterious force responsible for the accelerating expansion of the Universe. It represents about 70% of its total energy content.
Unlike gravity, which attracts objects together, dark energy pushes them apart. This effect is particularly visible in the vast cosmic voids, where its presence dominates.
The origin of dark energy remains one of the greatest mysteries in cosmology. Some theories suggest it is linked to empty space itself.
Understanding dark energy is essential to predict the ultimate fate of the Universe. Its study could reveal new physical laws.