I’m busy dealing with the challenges of being in a quantum superposition, but you’ve probably heard: BICEP2′s paper is now published, with some of its implicit and explicit claims watered down after external and internal review. The bottom line is as I discussed a few weeks ago when I described the criticism of the interpretation of their work (see also here).
There is relatively little doubt (but it still requires confirmation by another experiment!) that BICEP2 has observed interesting polarization of the cosmic microwave background (specifically: B-mode polarization that is not from gravitational lensing of E-mode polarization; see here for more about what BICEP2 measured)
But no one, including BICEP2, can say for sure whether it is due to ancient gravitational waves from cosmic inflation, or to polarized dust in the galaxy, or to a mix of the two; and the BICEP2 folks are explicitly less certain about this, in the current version of their paper, then in their original implicit and explicit statements.
And we won’t know whether it’s all just dust until there’s more data, which should start to show up in coming months, from BICEP2 itself, from Planck, and from other sources. However, be warned: the measurements ...