This issue, following an international conference held at the IKKM in September 2017, is devoted to what may very well be the broadest media-related topic possible, even if it is accessible only through exemplary and experimental approaches: Under the title of the »Mediocene«, it presents contributions which discuss the operations and functions that intertwine media and Planet Earth. The specific relation of media and Planet Earth likely found its most striking and iconic formula in the images of the earth from outer space in 1968/69, showing the earth—according to contemporaneous descriptions—in its brilliance and splendor as the »Blue Marble«, but also in its fragility and desperate loneliness against the black backdrop of the cosmic void. Not only the creation but also the incredible distribution of this image across the globe was already at the time clearly recognized as a media eff ect. In light of space fl ight and television technology, which had expanded the reach of observation, communication, and measurement beyond both the surface of the Earth and its atmosphere, it also became clearly evident that the Planet had been a product of the early telescope by the use of which Galileo found the visual proof for the Copernican world model. Nevertheless, the »Blue Marble« image of the planet conceives of Earth not only as a celestial body, but also as a global, ecological, and economic system. Satellite and spacecraft technology and imaging continue to move beyond Earth’s orbit even as they enable precise, small-scale procedures of navigation and observation on the surface of the planet itself. These instruments of satellite navigation aff ect practices like agriculture, urban planning, and political decision-making. Most recently, three-dimensional images featuring the planet’s surface (generated from space by Synthetic Aperture Radar) or pictures from space probes have been cir-culating on the Web, altering politico-geographical practices and popular and scientifi c knowledge of the cosmos. Today, media not only participate in the shaping of the planet, but also take place on a planetary scale. Communication systems have been installed that operate all over the globe.