How The Internet Travels Across Oceans

Submarine cables, according to the authoritative submarine cable map website, reveal a vast network of 493 active or actively under construction sub-sea internet cables crisscrossing the globe. These cables vary in length, from relatively modest 300-kilometer wires under the Black Sea to the gargantuan 6,600-kilometer Maria cable linking Virginia Beach in the US with Bilbao in northern Spain – a cable equivalent in weight to 24 blue whales. Worldwide, there's now approximately 1.5 million kilometers of undersea data wires, a significant infrastructure investment, typically costing between three and four hundred million dollars per transoceanic cable. These cables are not especially thick, roughly equivalent to the girth of a garden hose, but they are packed with layers of protective thixotropic jelly around the all-important fiber optic core, as well as multiple plastic sheaths and copper wiring to power the system. Despite their relatively slender appearance, these cables are capable of ferrying an impressive 100 gigabytes per second in data, with newer and forthcoming cables poised to transmit at speeds of up to 400 gigabytes per second.

 

A key technology enabling this remarkable data transmission is dense wavelength division multiplexing. This advanced technique allows data providers to utilize multiple wavelengths of light to convey information through fiber optics simultaneously, creating astonishing data speeds. At both ends of the cable, landing sites resembling buzzing data centers house the equipment necessary for this process.

 

The cables themselves are not simple long wires but rather feature repeaters every 70 to 100 kilometers along the seabed. These repeaters serve as amplifiers, ensuring that the signal strength remains strong over long distances. The cables also incorporate copper conductors capable of carrying up to 10,000 volts of DC to power these repeaters.

 

The process of laying these undersea cables is meticulous. Specialized cable-laying ships first coil the cables into vast cylindrical drums. Detailed planning and charting efforts go into plotting the perfect transoceanic route, avoiding locations prone to volcanic activity, earthquakes, mudslides, or heavy fishing. The cable is carefully spooled out from the back of the ship at a sedate pace of around 10 kilometers per hour. In the event of adverse weather conditions, the ship can break off, tie the cable to a buoy, and return when conditions improve. Accidents and outages on these cables do occur, sometimes due to natural disasters like Hurricane Sandy or the Fukushima earthquake, but most often as a result of human carelessness, such as trawler nets or wayward ship anchors.

 

Sharks have been known to nibble on these cables, and the U.S. government has consistently warned of potential interference from hostile foreign powers like Russia or China. Geopolitically, these undersea cables are significant, with concerns about potential access to sensitive networks and information.

 

Historically, nations or quasi-national telecom providers have funded the construction of these cables. The largest owner of undersea cables is America's AT&T, with a stake in approximately 230,000 kilometers of cable. China Telecom follows as the second-largest owner. Many cables are owned by consortia of up to 50 separate entities, including tech firms, local government agencies, and other businesses, spreading the initial cost but complicating decision-making in times of disruption.

 

Recently, major tech companies like Facebook, Google, and Amazon have invested heavily in undersea cable infrastructure, recognizing its critical role in their growth. These tech giants own vast stretches of cable networks, positioning themselves as key players in the undersea cable industry.

 

While technologies like Elon Musk's Starlink aim to provide wireless internet access, undersea cables remain the most cost-effective and efficient means of transmitting data over vast distances. Google and Facebook, for example, have announced joint initiatives to build undersea cables like Apricot, connecting multiple nations in the Asia-Pacific region.

 

In conclusion, the future of the internet still largely relies on undersea cables, despite the potential for wireless alternatives. As tech giants continue to invest in this infrastructure, it remains a vital and evolving component of our increasingly connected world.