If true, the discovery would force a new understanding of gravity and about our cosmos, as such a galactic flyby only makes sense if gravity weakens more slowly as galaxies drift apart than mainstream thinking suggests.
Indranil Banik, the PhD student who led the study, said: "The ring-like distribution is very peculiar. These small galaxies are like a string of raindrops flung out from a spinning umbrella. I found there is barely a 1 in 640 chance for randomly distributed galaxies to line up in the observed way. I traced their origin to a dynamical event when the Universe was only half its present age.
massive galaxies always orbited each other in a plane and would have scattered dwarf galaxies in their paths, perhaps explaining why the speeding dwarfs are in a plane also containing the Milky Way and Andromeda.
Mr Banik added: "In Einstein's gravity paradigm, hypothetical dark matter is always invoked. Such a high speed requires 60 times the mass we see in the stars of the Milky Way and Andromeda. However, the friction between their huge halos of dark matter would result in them merging rather than flying 2.5 million light years apart, as they must have done."