Under the sea: understanding your heavily wired world
It often feels like the internet is magically all around us, like air, but the reality is that it takes physical infrastructure of cables and wires to transmit data from a server to your computer or phone. Neal Stephenson once compared the earth to a computer’s motherboard because of the system of wires and cables that crisscross the globe.
Incredibly, the most important cables run under the ocean. Fiber optic cables at the bottom of the ocean transmit 99% of all transoceanic digital communication. They are what allow you to email a friend in Paris and Skype a colleague in China.
These submarine communication cables are vital to ensuring that the internet functions smoothly. They run through the Pacific, Atlantic, and Indian Oceans, and even run north through the Arctic Ocean to connect a Norwegian archipelago to the internet. This incredible TeleGeography map shows where all the cables run.
Despite the importance of these cables, few of us know how they work or what threats they face (like sharks!). Here’s a primer on the underwater world that powers your internet.
How Submarine Cables Work
Transoceanic cables have a much longer history than you might realize. Intercontinental telegrams were sent via cables in the ocean. The first message was relayed between Newfoundland and Ireland in 1858. By today’s standards, the messages were transmitted agonizingly slowly; a 98-word message from Queen Victoria to President James Buchanan took 16 hours to send. Despite this painful delay, they were still much faster than sending a ship to deliver messages.
Just as telegraph cables made it much quicker to send messages in the nineteenth century, today’s fiber optic cables make the speed of our internet faster.
The fiber optic cables are thin, varying from the diameter of a garden hose to the diameter of a Magic Marker. The cable is not laid directly on the ocean bed, but on a plough. Specifically modified ships lay down the cable, carefully avoiding coral reefs, sunken ships, and other ecological habitats and obstructions.
Merely coiling hundreds of miles of cable in a cargo hold can take between three to four weeks. But it’s worth the time and energy because fiber optic cables are the best way to send information. They can transmit information close to the speed of light, and are much better than satellites.
In Antarctica — the only continent relying on satellites and without a physical connection to the internet — internet speeds are slow and bandwidth is at a premium.
The Underwater World That Powers Your Internet
While the undersea cables transmitting our internet are important, they are also incredibly vulnerable. Everything from ships to natural disasters and even sharks can threaten these cables.
For reasons no one is sure of, sharks really enjoy chewing on fiber optic cables. Google now strengthens its cables with a layer of protective material meant to keep sharks and other fish away.
Entertaining as they may be, sharks are not the biggest threat to undersea cables. About 60% of cut cable incidents are caused by boats dropping their anchors or trawling by fishing vessels. It’s for this reason that cables are marked on navigational charts warning boaters not to drop anchor.
Natural disasters and seismic shifts can also disrupt cables. Even more interestingly, undersea cables are a prime target for espionage. Last year, American officials reacted uneasily to Russian ships near cables, speculating Russians may cut those lines if there is tension or conflict.
Russia is far from the only country interested in submarine cables. Tapping them is standard operating procedure for many countries, leading Brazil to lay its own cable specifically to avoid U.S. surveillance.
Fortunately, even if a shark or spy agency succeeds at cutting a particular cable, there is an entire network of other cables to pick up the slack. More than 200 cables run in the underwater world that powers our internet, making it possible for you to read this blog post whether you’re in Tallahassee or Tokyo.