Question: whats dark flow?

Clare Burrage answered on 17 Mar 2012:

When scientists talk about ‘dark something’ usually the dark means that it’s something we don’t understand. So dark matter is a type of matter that we know lives in galaxies, but we don’t really know what it is, dark energy is a type of energy that is making the expansion of the universe accelerate but we don’t know what this kind of energy can be.
Dark flow (as you might have guessed by now!) is a flow of galaxies through our universe that we don’t understand. We expect that the galaxies should be moving around randomly in the universe, but it seems like there’s a particular direction that they like to go.
Scientists still don’t agree though, on whether dark flow is actually happening, or whether it’s just a mistake in our measurements.