Engineering: large cogs meshing together, and diagrams of epicycloid curves. Colour lithograph by Stanislas Petit, ca. 1905. https://www.rawpixel.com/image/13951560/image-background-paper-cartoonFree Image from public domain licenseGrass Valley, United States. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3305454/free-photo-image-manufacturing-cc0-clothingFree Image from public domain licenseMechanics: various machines. Coloured engraving by J. Emslie, 1850, after himself. https://www.rawpixel.com/image/13961976/image-person-technology-public-domainFree Image from public domain licenseSubway. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3305738/free-photo-image-subway-light-tunnel-transportationFree Image from public domain licenseColorful light abstract background, free public domain CC0 photo. https://www.rawpixel.com/image/5926408/photo-image-background-public-domain-gradientFree Image from public domain licenseAir Force in Space (1995) illustrated by Tish Tompkins. Original public domain image from Wikimedia Commons. Digitally… https://www.rawpixel.com/image/10184890/image-astronaut-face-personFree Image from public domain licenseMagnetism: electrical equipment and magnetic phenomena. Coloured engraving by J. Emslie, 1850. https://www.rawpixel.com/image/13965909/image-space-art-compassFree Image from public domain licenseFree digital mixer image, public domain musical instrument CC0 photo. https://www.rawpixel.com/image/5921362/photo-image-background-public-domain-technologyFree Image from public domain licenseFree listening to music image, public domain electronic device CC0 photo. https://www.rawpixel.com/image/5918654/image-public-domain-black-technologyFree Image from public domain licenseBlack hole (2001) photo by XMM-Newton, ESA, NASA. Original public domain image from Wikimedia Commons. Digitally enhanced by… https://www.rawpixel.com/image/10184853/image-galaxy-person-spaceFree Image from public domain licenseFree web design wireframes on paper image, public domain design CC0 photo. https://www.rawpixel.com/image/5926265/photo-image-paper-public-domain-artFree Image from public domain licenseSecurity motivational poster (1950-1969) chromolithograph by NSA. Original public domain image from Wikipedia. Digitally… https://www.rawpixel.com/image/11221836/image-hand-person-vintageFree Image from public domain licenseAstronaut Edwin E Aldrin Jr, Lunar Module (LM) pilot descends from the LM, climbing down the ladder. Original from NASA.… https://www.rawpixel.com/image/418665/astronaut-edwin-aldrin-jrFree Image from public domain licenseCellarius Ptolemaic System from Andreas Cellarius Harmonia Macrocosmica (1660) chromolithograph art by J. van Loon. Original… https://www.rawpixel.com/image/10184766/image-face-hand-personFree Image from public domain licenseSolar array at Natural BridgesStaff working on the solar panel array at Natural Bridges National Monument. NPS photo by… https://www.rawpixel.com/image/4036957/photo-image-technology-person-natureFree Image from public domain licenseAgriculture Secretary Sonny Perdue, Maryland Governor Larry Hogan, Senior Advisor to the President Ivanka Trump and CEO… https://www.rawpixel.com/image/3307029/free-photo-image-worker-factory-manufacturing-plantFree Image from public domain licenseDebris plot photo by NASA. Original public domain image from Wikimedia Commons. Digitally enhanced by rawpixel. https://www.rawpixel.com/image/10184875/image-galaxy-space-skyFree Image from public domain licenseFull views of Mir Space Station after undocking during flyaround. Original from NASA. Digitally enhanced by rawpixel. https://www.rawpixel.com/image/440660/space-stationFree Image from public domain licenseAt Lawrence Livermore National Laboratory (LLNL), the Sierra supercomputer will be a 125-petaflops (floating point operation… https://www.rawpixel.com/image/3322311/free-photo-image-server-network-supercomputerFree Image from public domain licenseSolar cell panel. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3339459/free-photo-image-solar-energy-sun-panelsFree Image from public domain licenseCRS–8 first stage landing (2016). Original from Official SpaceX Photos. Digitally enhanced by rawpixel. https://www.rawpixel.com/image/2229746/official-space-photosFree Image from public domain licenseInterior of StorageTek tape library at NERSC. Free public domain CC0 photo. https://www.rawpixel.com/image/6042705/photo-image-tape-public-domain-technologyFree Image from public domain licenseFree inside of a watch in black and white image, public domain CC0 photo. https://www.rawpixel.com/image/5922234/photo-image-background-public-domain-freeFree Image from public domain licenseOptics: interference phenomena, exhibited by diffraction gratings. Coloured mezzotint by M. Rapine [1883], after B. Desgoffe. https://www.rawpixel.com/image/13968649/image-background-pattern-circleFree Image from public domain licensePhotograph of MSC-8 color patch outside spacecraft during docking. Original from NASA. 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Coloured process print by Cassell. https://www.rawpixel.com/image/13957739/image-stars-sun-circleFree Image from public domain licenseFree MacBook with analytics charts image, public domain CC0 photo. https://www.rawpixel.com/image/5926123/photo-image-background-public-domain-technologyFree Image from public domain licenseThe new firefighter breathing system is made up of an air bottle, a frame and harness, a face mask, and a warning device.… https://www.rawpixel.com/image/439932/firefighters-blazeFree Image from public domain licenseFree electrical estimator documents image, public domain documents CC0 photo. https://www.rawpixel.com/image/5924892/photo-image-papers-public-domain-freeFree Image from public domain licenseNiedervisse village. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3339450/free-photo-image-eco-sustainable-wind-powerFree Image from public domain licenseBlack transmission towers under green sky. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3286203/free-photo-image-public-utility-cable-cc0Free Image from public domain licenseThe Gemini-12 spacecraft during standup extravehicular activity with the hatch open. Original from NASA. Digitally enhanced… https://www.rawpixel.com/image/418677/the-gemini-12-spacecraftFree Image from public domain licenseRound gray hanging decor. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3286548/free-photo-image-product-wall-minimal-interiorFree Image from public domain licenseEngineering: large cogs meshing together, and diagrams of epicycloid curves. Coloured lithograph, 1905, by Stanislas Petit. https://www.rawpixel.com/image/13968889/image-paper-art-patternFree Image from public domain licenseA Wacom drawing tablet on a desk in a corner of a room. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3282907/free-photo-image-office-work-technology-laptopFree Image from public domain licenseFree close up hand typing on keyboard image, public domain CC0 photo. https://www.rawpixel.com/image/5921524/photo-image-background-public-domain-handFree Image from public domain licenseWooden pole of a minor overhead power line, unidentified location. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3286721/free-photo-image-electricity-public-domain-poleFree Image from public domain licensePatterned orange wallpaper. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3285203/free-photo-image-texture-lines-background-orangeFree Image from public domain licenseEngineering: a large cogwheel, front and side elevations. Coloured drawing, 1875, by []. https://www.rawpixel.com/image/13964613/image-background-paper-patternFree Image from public domain licenseThe recirculating electron accelerator seen inside Jefferson Lab’s Hall C located in Newport News, Va. For more… https://www.rawpixel.com/image/10994052/photo-image-person-mathematics-public-domainFree Image from public domain licenseSolar cell panel. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3339457/free-photo-image-solar-photovoltaic-panel-carbonFree Image from public domain licenseBlue light reflected in the surface of glossy swirling wires. 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