Large-Angle Anomalies in the Microwave Background

Understand

Several claims have been made of anomalies in the large-angle properties of the cosmic microwave background anisotropy as measured by WMAP.

• In most cases, the statistical significance of these anomalies is hard or even impossible to assess, due to the fact that the statistics used to quantify the anomalies were chosen a posteriori.
• On the other hand, the possibility of detecting new physics on the largest observable scales is so exciting that, in my opinion, it is worthwhile to examine the claims carefully.
• I will focus on three particular claims: the lack of large-angle power, the north-south power asymmetry, and multipole alignments.