The Cosmic Microwave Background (CMB) is the thermal glow from the Big Bang birth of our Universe. Studying its pattern has taught us an enormous amount about the content, evolution and fate of the Universe in which we find ourselves. Basic theory allows us to push our understanding back to an enormously high energy state, and infer the very particular set of conditions which pertained at that time - almost uniform plasma with Gaussian, scale free perturbations. However, we need an even more radical theory dubbed "Inflation" to explain how those conditions were set up.
