Galaxies that exist in the vast emptiness of cosmic voids

Space · Published 18 October 2026 Swipe more like this →

In short: Most galaxies huddle together in dense sheets and filaments, but some live in near-total isolation. These void galaxies are unique laboratories for understanding galactic evolution, potentially offering a pristine look at how stars form when there are no neighbors to interfere.

Cosmological voids are immense spaces between the large-scale structures of the universe. While most galaxies reside in dense walls or filaments, void galaxies are situated within these empty regions. They are often linked by "void filaments" or tendrils—smaller, straighter versions of the massive structures that define the cosmic web. Because they lack the gravitational influence of surrounding clusters, these filaments can appear notably more linear than their counterparts in denser areas. These smaller structures can be substantial enough to host poor galaxy clusters. They represent less massive versions of the primary filaments that outline cosmic voids.

The origin of these isolated systems is a subject of active astrophysical theory. One prominent theory suggests that void galaxies are remnants of larger galactic filaments that were pulled away by the gravity of major superclusters. This process effectively "stretches" the voids, leaving galaxies like the spiral MCG+01-02-015 stranded in less densely populated regions as they move outward. In this view, a void galaxy is not just born alone; it may be an outcast from a more crowded neighborhood. This gravitational pulling action is what causes specific regions like the Boötes Void to expand over time. These orphaned systems are sometimes categorized as being left behind during these large-scale movements.

Because of their isolation, these galaxies are considered pristine examples of galactic evolution. Unlike most galaxies that interact with neighbors through mergers or tidal forces, void galaxies likely formed from pure intergalactic gas. They provide scientists with a unique opportunity to study the fundamental processes of galaxy formation in a "clean" environment, free from the complex dynamics of the crowded cosmic web. Researchers believe these objects have very few neighbors nearby. This lack of interaction allows them to serve as a baseline for how galaxies develop in the absence of external interference.

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