Re: The explanation of interference is slightly wrong in the article...
Is the Milky Way moving or is it not rather space that expands.
The movement of the Milky Way is measured by checking relative velocities of all the crap around it out to a billion LY or so.
"Space expanding" is something else, it just means everything is moving away from everything else by sheer inertia (in imagery along the fourth dimension, like the coins on the expanding balloon moving along the third dimension which doesn't actually exist on the balloon surface). If the coins exhibit mutual attraction, there can be serious movement on the balloon surface (plus local crumbling)