The Physical Internet: Cables, Satellites, and More

Right now, almost all of your “wireless” life is riding a glass thread thinner than a hair, stretched across the ocean floor. In this episode, we’ll dive under the waves, into orbit, and through the air to trace the very real hardware behind the so‑called cloud.

Ninety‑five percent of the world’s intercontinental data doesn’t fly through space; it crawls along the seafloor inside fiber‑optic cables that ships sometimes snag, earthquakes occasionally snap, and governments quietly map and monitor. Above that lattice of glass, a second internet rides the sky: dense constellations of low‑Earth‑orbit satellites like Starlink, high‑altitude microwave links hopping between towers, and the cellular and Wi‑Fi networks you actually touch. Each layer has a personality: fiber offers huge capacity and stability, satellites trade raw speed for reach, and radio links navigate terrain and politics. In practice, your messages may start on home Wi‑Fi, jump to a nearby cell tower, dive into a terrestrial fiber backbone, plunge into a transoceanic cable, then surface through a satellite link in a remote region—an intricate route shaped by physics, cost, and control.

Together these layers behave less like a neat stack and more like a constantly shifting traffic system. Routing software is always re‑calculating “shortest path,” but shortest can mean different things: fewest milliseconds, lowest cost, or most resilient if something breaks. Undersea repairs can take weeks, so operators may steer flows across entirely different oceans or through space. And because links are owned by competing companies and countries, business deals and treaties can matter as much as physics in deciding how your packets actually travel.