This is huge. See New York Times article, which (I think) wasn't yet published in time for any of the other diaries: Detection of Waves in Space Buttresses Landmark Theory of Big Bang.
A ground-based Cosmic Microwave Background telescope in Antarctica is claiming a 5-sigma detection of a signature of gravity waves in the cosmic microwave background.
(In science-speak, what they’re seeing is a B-mode polarization signal in the CMB: a polarization field on the sky with a non-zero curl. Gravity waves are the only physical mechanism* which tends to produce B-mode polarization in the CMB. This measurement confirms the Planck satellite, which saw hints of the same thing, but not nearly so unambiguously.)
* Currently thought of. It’s easy to invent structures which would make B-mode polarized light, but they’re a little complicated, there’s no obvious reason why the hot gas of the early universe would tend to organize itself in such patterns.
Update: Another diary on the topic: "Smoking gun proof found of key Big Bang process" which has a video and link to last night's OND that also includes links to other news articles on the topic.
Human-speak below the fold...