submarine cables today

Let’s say you live in New York and you have a friend in London. One day you decide to call your friend. You whip out your cell phone, punch in his or her number, the phone bleeps twice in a very British-style way and your friend answers. You might assume, in our modern high-tech world, that the electrical impulses of your call are being bounced off satellites in orbit. After all, that’s how telecommunications works these days, right?

Wrong. If you make 100 calls to your friend, chances are good that 99 of those calls will be transferred not by satellite signals, but by submarine cables–big wires cris-crossing the ocean floor, carrying massive amounts of data every second of every day. These cables are so important to the day-to-day functioning of the world that you could say they literally knit the planet together. Satellites, while useful for some forms of communication, are comparatively slow and carry less information. A cable across the ocean floor, especially the sort of super high-tech fiber optic cables that have been laid down since the turn of this century, is much more reliable, and, once you get past the staggering cost of installing it, it’s much more cost-effective than satellites. Most international telephone calls will probably continue to be carried primarily on submarine cables for the foreseeable future. Your call to London only hits the airwaves at the beginning and end of its journey–the transmission from yours and your friend’s cell company’s towers to your hand-held devices. The rest of your call is traveling along the bottom of the Atlantic. The photo at the top of this article, which looks like junk on the beach, is actually several of the world’s most important cables coming ashore in Scotland.

There’s so much to learn about submarine telecom cables that it would take you a lifetime, or at least a career, to become an expert on the subject. Suffice it to say that these little threads have technology, economy and history surrounding them every bit as impressive as the Apollo moon landing. Imagine the staggering engineering issues involved, for instance, in laying a telecommunications cable across the vast, deep, cold Pacific Ocean linking the USA to Asia. Would you believe somebody figured out how to do it in 1902? How do you fix a cable that breaks on the bottom of the ocean, miles down in pitch-black water where human beings can’t go? I have absolutely no idea, but clearly someone does, because they do it all the time.

At least when we’re talking about transatlantic cables, these fascinating wires have a long history. The first attempt at connecting telegraphs from the United States to Britain was made in 1858. It was successful, but only for a month. The U.S. Civil War and the time needed to develop better technology made it 16 years before the next attempt succeeded, but by the late 1860s, you could stand in a telegraph office in Manhattan, send a dot-dash message to London and have it received in a couple of minutes–if you could afford it, that is. Telecom cables in the 19th and first half of the 20th century were insulated with a kind of natural rubber called gutta percha. Telegraph cables were so important to national security at this time that securing reliable supplies of gutta percha became a significant foreign policy objective for the U.S. and Britain between 1860 and the 1930s.

submarine cables in 1901

This is a map of one company’s submarine telecom network–in 1901. Click for a larger/more detailed image.

Would you believe, with all this amazing technology, that the first telephone cable (as opposed to telegraph) was not laid across the Atlantic until 1956? The tech exploded after the Second World War. The coaxial cables laid across the Pacific and Indian oceans in the 1960s are still quite usable, though they are economically unfeasible due to bandwidth limitations. To minimize breaks and security issues, submarine cables started being buried–yes, under the ocean floor–in 1980. How the hell do you bury a telecom cable miles down in pitch darkness, bitter cold and intense water pressure? Again, I have no idea, but they do it.

If telecom signals are so dependent on these cables, what happens if they break or something else goes wrong? A lot. It happened several times in 2008 alone, and resulted in huge Internet and phone blackouts across the Middle East, India and other parts of Asia. In December of that year, a ship’s anchor–yes, one ship–cut 3 major cables across the Mediterranean, which resulted in a lot of “404-File Not Found” errors in Egypt and nearby places. If one ship with a dragging anchor can take out Egypt’s internet accidentally, what do you think a terrorist group or one major industrialized country at war with another could do on purpose? Yeah, it’s like that.

The simple truth is, when it comes to transmitting data, there’s a whole lot more going on under the waves than there is up in the sky. That is not likely to change any time soon.

The photo at the top of this page was taken by Wikimedia Commons user “jmb” and used under the GNU Free Documentation License. The 1901 map is a public domain image.