Are the galaxies in alignment? ESO, ESA/Hubble, NASA. Digitized Sky Survey/Davide de Martin

The dwarf galaxies orbiting the much larger galaxy Centaurus A appear to be moving along the same plane as one another. If this surprisingly coordinated dance around a galactic hub is common across the cosmos, we may have to go back to the drawing board on galaxy formation theory.

But that’s a big, big if. Theories on galaxy formation suggest that dwarf galaxies should be captured by larger galaxies into random orbits based on the direction they came from. In this view, large galaxies are …