Cosmic Voids Mystery

The cosmic web is not just filaments and clusters — it is mostly empty voids. These vast regions of nearly empty space span hundreds of millions of light-years and contain far fewer galaxies than average. The Bootes Void, one of the largest known, is 330 million light-years across and contains only about 60 galaxies.

Voids are not completely empty, but the galaxies within them tend to be smaller, bluer, and more actively forming stars than galaxies in denser environments. Studying void galaxies shows how galaxies evolve in isolation, free from the constant gravitational interactions and mergers that shape life inside a crowded cluster.