(non-random patterns in peculiar velocity of galaxy clusters)
Dark flow is a pattern in the movement of galaxy clusters
suggesting a force other than whatever powers
Hubble's law, such as might the
gravity of a compact but very massive object.
Evidence was announced in 2008 based upon Wilkinson Microwave Anisotropy Probe data
as well as galaxy cluster data, and has since been debated.
The concept has inspired exotic explanations from astrophysicists
The general direction of the dark flow is toward the Great Attractor,
but they could be independent.