Is the Universe lop-sided?

Since the standard cosmological model is such a good fit to the cosmic microwave background anisotropy data, a great deal of attention has focused on hints of "physics beyond the standard model".  One particular large-scale "anomaly" that has been noted is that there appears to be more power on one side of the CMB sky than the other.  The statistical evidence for this hemispherical asymmetry (or dipole modulation) of the CMB sky is on quite shaky ground, as will be described - we should be skeptical of all such a posteriori statistical claims! Nevertheless, if such an effect could be shown to be significant it would be enormously important, since it would demonstrate the breaking of statistical isotropy on the largest scales, hence pointing to new physics. I will describe ideas for early Universe models that could generate such asymmetrical skies, and discuss prospects for future observations to further probe these models.

Speaker: Douglas Scott, Univ. of British Columbia