You can choose to view a single map, or compare multiple maps by tilting your device. A sky reference map is also included to show the galactic coordinates, notable Milky Way components, and microwave point sources. Cosmic Microwave Background (CMB) is the afterglow radiation from the Big Bang. Its temperature is extremely uniform, but with tiny fluctuations as you will see in these maps. In 1992, COBE satellite made the first detection of the CMB fluctuations. The following WMAP and Planck mission were able to scan the sky at better and better resolution. The successes of these CMB observations have provided us great understanding of the Universe over the last decades. Check the Wikipedia page for more details: http://en.wikipedia.org/wiki/Cosmic_microwave_background This app is designed and made by Qingqing Mao at Vanderbilt University for the purposes of astronomy education and demonstration. The included CMB maps are generated by NASA and ESA. COBE, WMAP and sky reference image credits: NASA / WMAP Science Team. Planck image credits: ESA and the Planck Collaboration. Author's personal website: http://mqq.io Suggestions and feedback are very welcome. Please leave your review, or visit author's website for contact information.