While the spectrum and the temperature have been successfully measured by NASA Satellites, we are just now beginning to characterize the polarization. A high sensitivity map of the polarization will verify one of the major pillars of the gravitational instability induced model of the formation of cosmological structures. Higher sensitivity maps of the polarization will chart out the detailed anisotropies in the sky, and may eventually lead to detection of an extremely faint signal left by primordial gravity waves, left from the era of Inflation.
I will be describing a series of experiments, Maxipol, EBEX, and PolaRbeaR. Maxipol was a joint UC Berkeley-University of Minnesota balloon-borne project that flew in 2003. I will be describing the results and lessons learned from this flight. PolaRbeaR is the next generation in polarization measurements. This ground-based experiment has a 3.5m telescope coupled to a large array of bolometers. EBEX is a long-duration balloon-borne experiment sharing many technological features with PolaRbeaR. These experiments will be fielding in the next few years.