The Powers of Ten by Charles and Ray Eames announces itself as “A film dealing with the relative size of things in the universe,” and in it, we see two people enjoying a picnic on a sunny day before the view zooms up and away to show the park where they sit, the city around the park, the continent, the whole globe, and progressively farther into space, lightyears beyond the initial scene. It then moves back in for a close-up of the hand of the picnicker, travelling deep into the microscopic realm. Zachary Horton calls this effect the “cosmic zoom,” a trope that has influenced countless media forms over the past seventy years. The Cosmic Zoom uses this visual and conceptual flight through the scales of the universe as a starting point to develop a cross-disciplinary theory of scale as mediated difference. It considers the origins of our notions of scale, how scalar mediation functions differently in analog and digital modes, and how cosmic zoom media has influenced both scientific and popular understandings of the seen and unseen world. These considerations, Horton shows, are vital to addressing the major questions of both climate change and big data, which he treats as two facets of a single issue: scalar mediation. Through analyses of literature, film, digital media, and database history, Horton brings our obsession with scale into sharper focus, establishing a much-needed framework for thinking about scale across multiple domains and disciplines.