Dark Flow

"As if the mysteries of dark matter and dark energy weren't vexing enough, another baffling cosmic puzzle has been discovered.

Patches of matter in the universe seem to be moving at very high speeds and in a uniform direction that can't be explained by any of the known gravitational forces in the observable universe. Astronomers are calling the phenomenon "dark flow."

The stuff that's pulling this matter must be outside the observable universe, researchers conclude."


Now am I reading this wrong or is someone positing that gravitons travel faster than light?

Now I can understand that two observers in our universe that can see each other would have different observable universes, but this seems to imply that the thing (mass) that is acting lies well outside the observable universe for either. If so how is it acting?

---

"...The stuff that's pulling this matter must be outside the observable universe, researchers conclude."

What threw me off at first is the article makes two claims for 'observable universe':

"When scientists talk about the observable universe, they don't just mean as far out as the eye, or even the most powerful telescope, can see... The universe is thought to have formed about 13.7 billion years ago...
"The structures responsible for this motion have been pushed so far away by inflation, I would guesstimate they may be hundreds of billions of light years away, that we cannot see even with the deepest telescopes because the light emitted there could not have reached us in the age of the universe," Kashlinsky said...

I think the "long and the short of it" is they (scientist) have seen something, they don't know what's causing it, and they think it's far enough away that our earth-bound telescopes won't ever see it since we're too far away for the light to reach us (at "the speed of light").

As for having two observers, that would help if the second observer (since "We're number one!") were 'closer to the action' and able to pass their observations back to us, but since we're currently alone in this, we have to make 'best guesses' based on the 'single observation point' of Earth.

---