More doubts about a repulsive "dark energy" arise every day. In a new paper accepted by Physical Review D, Christos Tsagas of Aristotle University in Greece suggests that apparent acceleration of the universe could be an illusion. The cause would be our galaxy being part of a "dark flow". Such a flow would make expansion of the universe appear nonuniform, creating the illusion of acceleration. The paper builds on work by Alexander Kashlinsky here in NASA Goddard Space Flight Center.This blog reported Kashlinsky's work back in September 2008, Going With the Flow. That year Kashlinsky reported that clusters of galaxies, including our Milky Way, appear to be moving at 600 km/sec toward some unseen attractor. What kind of enormous object could cause this flow is unknown, but it could be a super-sized ultra massive Black Hole. Old models of cosmology can not even account for the Black Holes within galaxies. Such immensely massive objects, along with the illusion of acceleration, are predicted by GM=tc^3 and a changing speed of light.