Filament (cosmology)

In cosmology, a filament is one of the largest structures in the universe, forming the cosmic web that connects galaxies across billions of light-years. These are thread-like formations of gas, dark matter, and galaxy clusters stretched along the spatial boundaries between vast empty voids. Filaments represent the scaffolding of structure left behind from the Big Bang, shaped by gravity pulling matter into elongated arrangements.

Filaments typically span tens to hundreds of millions of light-years and contain thousands of galaxies. They're complementary to cosmic voids—the enormous empty regions that constitute most of the universe's volume. The filamentary pattern emerges naturally from dark matter collapse and is confirmed through large-scale astronomical surveys like the SDSS.

Understanding filaments helps cosmologists map the universe's large-scale structure, test theories of gravity and dark energy, and refine models of how galaxies form and evolve. They reveal that despite the universe's vastness, matter clusters into an almost network-like geometry—a grand-scale hierarchy of organization.

Related

Cosmic web, Large-scale structure, Dark matter, Galaxy clusters, Cosmological simulation, Observational cosmology