This animation explains how the wealth of information that is contained in the all-sky map of temperature fluctuations in the Cosmic Microwave Background (CMB) can be condensed into a curve known as the power spectrum.

The temperature of the CMB exhibits fluctuations on a variety of angular scales on the sky. The animation shows six different maps that depict the relative 'power', or strength, of the fluctuations at different angular scales. The maps correspond to different regions of the curve, starting at angles of ninety degrees on the left side of the graph, through to the smallest scales – just a fraction of a degree – on the right hand side.

By studying the peaks in the power spectrum curve, cosmologists can extract information regarding the ingredients of the Universe, such as ordinary matter, dark matter and dark energy, and the overall geometry of the Universe.

Credits: ESA and the Planck Collaboration