Physics Colloquium Series, Fall 2009 and beyond

The Cosmic Microwave Background Radiation is our most important source of information about the early universe. Many of its features are in good agreement with the predictions of the so-called standard model of cosmology -- the Lambda Cold Dark Matter Inflationary Big Bang. However, the large-angle correlations of the microwave background exhibit several closely related statistically significant departures from the standard model. The lowest multipoles seem to be correlated with each other, rather than statistically independent as inflationary theory demands. Indeed, they also seem to be correlated with the geometry of the solar system, suggesting that they are not cosmologically produced. Even stranger, when we avoid the part of the sky that is contaminated by the galaxy, we find that there are essentially no large angle correlations. The ripples in the CMB may be the sound of the cosmic symphony, but why are the tuba and the bass very quietly playing the wrong music?