There’s coverage here and there about a new “dark flow” that astronomers have spotted out on the edge of the cosmos. A quick scan of the paper shows it to be pretty cool stuff.

Basically, the team tracked x-ray clusters of galaxies by watching how they scattered the Cosmic Microwave Background (CMB), the ubiquitous radiation left over from before the Big Bang. They found a “strong and coherent bulk flow” of those clusters that could well be billions of light years across.

Whatever’s causing this cosmic slide is probably outside of the observable universe. That would appear to undermine a theory known as “inflation,” which posits that a growth spurt moments after the Big Bang made the cosmos flat and homogeneous. As an alternative, the authors suggest that the galaxies may be responding to stuff that inflation pushed to beyond our universe’s horizon.

Image: NASA/WMAP/A. Kashlinsky et al.