Actually, one submarine per each cable, says Tim Stronge, researcher at TeleGeography, which tracks the commercial submarine cable industry.
says the cables run closer when they're near the shore but track different paths, especially out in the ocean.
That would make it 15 submarines for the 15 cables connecting the eastern U.S. to Europe (the 16th is going into operation soon).
"And if you eliminated all the trans-Atlantic connectivity, well, there's trans-Pacific connectivity you would have to address as well.
To cut all those is even more of a fanciful proposition," Stronge
also says that much of what regular users look for online, like videos and searches and websites, is hosted domestically and would remain unaffected even in the event of every single U.S.-connected cable going black.
"The industry is built to be robust; it's built for failure," he
Typically, the owners of the cable systems have to deal with cuts near the shore, caused by fishers or dragging anchors.
The cables in shallow waters are often especially armored for those threats.
Far in the ocean, they're just tiny fiber-optic wires inside a plastic tube, and rarely get disrupted (usually in natural disasters like earthquakes).
It costs anywhere from tens of thousands to $1 million or more to lift a deep-sea cable from the bottom of the ocean and work on it, according to Schofield and Stronge
"Let's say some foreign entity, some evil doer, like a James Bond villain, cut every single undersea fiber-optic cable connection to the United States," says Stronge
, "well, we do still have satellite."