Summary
Highlights
Ninety-nine percent of all internet traffic relies on a hidden network of undersea cables. There are 493 active or under-construction sub-sea internet cables globally, totaling 1.5 million kilometers. These cables, costing hundreds of millions of dollars each, are surprisingly thin, about the girth of a garden hose.
These cables can ferry an impressive 100 gigabytes per second, with newer ones reaching 400 gigabytes per second, thanks to dense wavelength division multiplexing (DWDM) which uses multiple light wavelengths simultaneously for astonishing data speeds. Repeaters, spaced every 70-100 kilometers, amplify the signal, powered by up to 10,000 volts of DC carried by copper conductors.
Cables are coiled onto specialized ships, and their routes are meticulously planned to avoid volcanic activity, earthquakes, mudslides, and heavy fishing areas. They are laid at a slow pace of about 10 kilometers per hour. To protect against damage, cables near shore are armor-plated and often buried in dedicated trenches. Sharks have also been observed nibbling on these cables.
Accidents and outages, often caused by natural disasters like hurricanes or earthquakes, and human carelessness from fishing nets or ship anchors, are common. Geopolitical implications are significant, with governments warning of interference from hostile powers. Historically, nations and telecom providers owned these cables, but increasingly, tech giants like Facebook, Google, and Amazon are investing heavily in their own vast networks to fuel their growth.
Despite advancements like Starlink, undersea cables remain the cheapest and most efficient way to transfer vast amounts of data over long distances. The future sees continued investment, with projects like the Apricot cable and the 45,000-kilometer '2 Africa' cable, demonstrating that this subaquatic network will remain crucial for global internet connectivity for the foreseeable future.