ABSTRACT
One of the most important discoveries of the 20th century was the detection of the cosmic microwave background (CMB). Arno Penzias and Robert Wilson serendipitously detected the CMB in 1965 while making measurements at a frequency of 4080 MHz. The detection of the CMB was the crucial evidence in favor of a Big Bang model over other cosmological models such as the Steady State model, since it showed the Universe did have a hot and dense early phase. One of the first space missions devoted to the study of the CMB was the Cosmic Background Explorer (COBE) which was launched in 1989. Thus, anisotropies in the CMB on smaller angular scales were impossible to measure with COBE. The CMB spectrum and the CMB anisotropies provide important information about the nature of our Universe; however there is one more measurable quantity beyond the spectrum and spatial distribution and that is polarization.
