Screens brighten with the flow of words. Perhaps they are emails, hastily scrawled on smart devices, or emoji-laden messages exchanged between friends or families. On this same river of the digital, millions flock to binge their favorite television programming, to stream pornography, or enter the sprawling worlds of massively multiplayer online roleplaying games, or simply to look up the meaning of an obscure word or the location of the nearest COVID-19 testing center.

Whatever your query, desire, or purpose, the internet provides, and all of the complexity of everything from unboxing videos to do-it-yourself blogs are contained within infinitely complex strings of bits. As they travel across time and space at the speed of light, beneath our oceans in fiber optic cables thinner than human hairs, these dense packets of information, instructions for pixels or characters or frames encoded in ones and zeros, unravel to create the digital veneer before you now. The words you are reading are a point of entry into an ethereal realm that many call the "Cloud."

While in technical parlance the "Cloud" might refer to the pooling of computing resources over a network, in popular culture, "Cloud" has come to signify and encompass the full gamut of infrastructures that make online activity possible, everything from Instagram to Hulu to Google Drive. Like a puffy cumulus drifting across a clear blue sky, refusing to maintain a solid shape or form, the Cloud of the digital is elusive, its inner workings largely mysterious to the wider public, an example of what MIT cybernetician Norbert Weiner once called a "black box." But just as the clouds above us, however formless or ethereal they may appear to be, are in fact made of matter, the Cloud of the digital is also relentlessly material.

To get at the matter of the Cloud we must unravel the coils of coaxial cables, fiber optic tubes, cellular towers, air conditioners, power distribution units, transformers, water pipes, computer servers, and more. We must attend to its material flows of electricity, water, air, heat, metals, minerals, and rare earth elements that undergird our digital lives. In this way, the Cloud is not only material, but is also an ecological force. As it continues to expand, its environmental impact increases, even as the engineers, technicians, and executives behind its infrastructures strive to balance profitability with sustainability. Nowhere is this dilemma more visible than in the walls of the infrastructures where the content of the Cloud lives: the factory-libraries where data is stored and computational power is pooled to keep our cloud applications afloat.