Dark matter does not directly show "bridges" between galaxies. However, the presence of dark matter is inferred through its gravitational effects on visible matter, such as stars and galaxies. These gravitational effects, in turn, play a role in the large-scale structure of the universe, including the distribution of galaxies and the formation of cosmic filaments and galaxy clusters.
Dark matter is an invisible form of matter that does not interact with light or other electromagnetic radiation, making it difficult to directly detect or observe. Its existence is primarily inferred from its gravitational effects on visible matter. Observations of the rotation curves of galaxies, the motion of galaxies within galaxy clusters, and the gravitational lensing of light from distant objects all indicate the presence of additional matter beyond what can be accounted for by visible matter.
The distribution of dark matter is thought to be more extended than the distribution of visible matter. It forms a cosmic web-like structure, where filaments of dark matter connect galaxy clusters and groups. These filaments, along with voids and walls, make up the large-scale structure of the universe. It is along these filaments that galaxies tend to form and cluster, giving the appearance of bridges or connections between them.
While we cannot directly observe or map dark matter on small scales, computer simulations based on the laws of gravity and our understanding of the early universe's conditions help us model and visualize the large-scale distribution of dark matter. These simulations suggest that dark matter plays a significant role in shaping the cosmic web structure, influencing the growth and evolution of galaxies and their clustering patterns.
So, while dark matter itself does not manifest as visible bridges between galaxies, its gravitational influence on visible matter contributes to the structures and connections we observe on large scales in the universe.