In 2025, astronomers reported one of the largest rotating structures ever found: a cosmic filament some 50 million light-years long, holding close to 300 galaxies, with many of them turning in step with the filament as a whole. The coordinated motion is difficult to reconcile with the way galaxies are thought to acquire their spin...

Galaxies are thought to get their spin early, through what is called tidal torque: as matter collapses under gravity, the uneven pull of its surroundings sets it turning. On that picture, a galaxy’s spin is shaped mostly by its own local patch of the universe, and there is no obvious reason for hundreds of galaxies, spread across tens of millions of light-years, to share a single coordinated rotation tied to the filament around them...

The question underneath is an old one, which is where galaxies get their angular momentum. This filament has not answered it, but it has handed the problem a large and awkward new clue.