Bartosz Ciechanowski writes long, detailed explanatory articles about physics, math and engineering that are full of interactive, animated diagrams. His article on GPS, posted last January, digs down into all its fundamentals, from the principles of trilateration to the orbital mechanics of GPS satellites to exactly what a GPS signal consists of. “It’s fascinating how much complexity and ingenuity is hidden behind the simple act of observing one’s location in a mapping app on a smartphone. What I find particularly remarkable is how many different technological advancements were needed for GPS to work.”