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"With each interaction, Alexa is training to hear better, to interpret more precisely, to trigger actions that map to the user's commands more accurately, and to build a more complete model of their preferences, habits and desires. What is required to make this possible? Put simply: each small moment of convenience - be it answering a question, turning on a light, or playing a song - requires a vast planetary network, fueled by the extraction of non-renewable materials, labor, and data. The scale of resources required is many magnitudes greater than the energy and labor it would take a human to operate a household appliance or flick a switch. A full accounting for these costs is almost impossible, but it is increasingly important that we grasp the scale and scope if we are to understand and govern the technical infrastructures that thread through our lives. III The Salar, the world's largest flat surface, is located in southwest Bolivia at an altitude of 3,656 meters above sea level. It is a high plateau, covered by a few meters of salt crust which are exceptionally rich in lithium, containing 50% to 70% of the world's lithium reserves. 4 The Salar, alongside the neighboring Atacama regions in Chile and Argentina, are major sites for lithium extraction. This soft, silvery metal is currently used to power mobile connected devices, as a crucial material used for the production of lithium-Ion batteries. It is known as 'grey gold.' Smartphone batteries, for example, usually have less than eight grams of this material. 5 Each Tesla car needs approximately seven kilograms of lithium for its battery pack. 6 All these batteries have a limited lifespan, and once consumed they are thrown away as waste. Amazon reminds users that they cannot open up and repair their Echo, because this will void the warranty. The Amazon Echo is wall-powered, and also has a mobile battery base. This also has a limited lifespan and then must be thrown away as waste. According to the Ay

Unlike conventional micro-transistors, magnetic tunnel junctions don't use the electrical charge of electrons to store information, but take advantage of a quantum-mechanical property that electrons have, which is referred to as "spin." Known as spintronics, computing technology based on magnetic tunnel junctions is still very much in the experimental phase, and applications are extremely limited. For example, the technology is used in aircraft and slot machines to protect stored data from sudden power outages. This is possible because magnetic tunnel junctions process and store information by switching the orientation of nano-scale magnets instead of moving electrons around as regular transistors do.

The synthesis of structurally complex organic molecules is the first task in the discovery of functional compounds needed for new technologies, including those in medicine and flexible electronics. Starting with relatively simple, purchasable reactants, the process involves sequences of chemical reactions in which the complexity of the molecules produced gradually increases with each step towards the final target. The sequences can be linear, or convergent (different parts of the target molecule are made in separate sequences and then joined together). To ensure that large amounts of the final product are prepared, each synthetic step must be high-yielding and reproducible, and must generate few side products.

An international research team from Germany and France has created structures in which light fields interact with electrons so strongly that the quantum vacuum itself is significantly altered. Using extremely short bursts of light, they interrupted this coupling much faster than the timescale of a vacuum fluctuation and observed an intriguing ringing of the emitted electromagnetic field, indicating the collapse of the vacuum state. Their key achievement could improve our understanding of the nature of nothingness-the vacuum of space itself, paving a way toward photonics exploiting vacuum fluctuations. The results are published in the current issue of Nature Photonics.