Submarine cables

Adapted from:

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(Click on the picture to zoom in)

(A screenshot of the interactive Submarine Cable Map. Credit: Courtesy of Submarine Cable Map)

Because mobile phones, Wi-Fi and Bluetooth are almost everywhere, it may seem like we don’t need wired devices any more – everything seems to manage wirelessly. But the truth is that there are more wires in the world than ever before – you just can’t see them! The reason is that those wires are strung along the bottom of the world’s oceans – submarine communications cables are faster and cheaper than satellites. In fact, the first transatlantic cables were actually laid in 1854!


99% of internet traffic across the oceans goes under the ocean via cables (which are just the width of garden hoses in deep water and the width of Coke cans in shallow water), which are laid on the very bottom of the sea floor. The cables can last on the ocean floor for 25 years.The cables are thousands of miles long, and in some places are laid as deep as Everest is tall! The wires are strung along the ocean bed by large tankers, called Cable Layers, which carry enough cable to go across the entire Atlantic Ocean.

Sharks like gnawing on submarine communications cables, which may be to do with electro-magnetic fields, but we don’t really know why. So companies such as Google are shielding their cables in shark-proof wire wrappers. They can also be broken, by fisherman, or be undersea earthquakes. If they get broken then the boats repair them within 10 days:

In some places, the cables are laid right over the beach and people have no idea they are treading on the internet!

But the biggest threat to these cables is humans, not sharks or other sea life. “The majority of the disruptions of our undersea network come from people dropping an anchor off their boat and hitting the cable, or a fisherman dragging a net on the bottom of the sea floor,” Nicola Starosielski explains — not exactly the usual cause that comes to mind when Google fails to reload!

In Egypt in 2008, multiple cables broke in succession. Reports indicated the damage was due to ships dropping anchors in the area (although videos didn’t show any ships in the area at the time!). The resulting outage was huge, disconnecting approximately 60 million people in India, 12 million in Pakistan, six million in Egypt and almost five million in Saudi Arabia.

The Arctic Fibre Project is exploring laying fiber-optic cables in the Arctic Ocean. “We’ve never had a cable that has gone through the Arctic Ocean,” Starosielski says. The cables would link Japan to the United Kingdom could zap data from one end to the other in just 154 milliseconds. But this a very expensive job.

You can see an interactive map of submarine cables by clicking here.

If you want to learn more about how the cables are laid, & what they look like, there is lots of detail and great photos here






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About nic schofield

I’m a primary schools computing technician, interested in teaching children, their teachers & their parents, about IoT, computational thinking and implications of technology on their lives and encouraging children to think critically about technology to influence change in the world.

9 thoughts on “Submarine cables

  1. It’s kind of weird how all our searches go to Los Angeles and back just to answer such a small question. It takes less than half a second when to look it up in a book it would take about 50 seconds 🙂


  2. I wonder how long we’ve been able to do search’s so quickly as it’s not been to long since the time when you’d have to wait like 10 seconds.


    • @Ellie: Ellie, the map’s on the wall – which do you think is the furthest place from the US? (Don’t forget the world is round!). Maybe use Google Earth?


  3. The are loads of cables on the map. It’s good that they are covering the cables so that the sharks don’t chew at it. Did the damage affect anyone in London or was it just those places?


    • I don’t know if London’s internet has ever been damaged by sharks, Priya! Maybe you could research it & let us know?


  4. I have Skyped a friend in Japan a few times and I thought it took less than 100 milliseconds.


  5. I still can’t believe that it takes less than 0.5 seconds for a Google search to go all the way to los angles and back.


  6. WOW! who would have guessed there were cables after all this talk about modern electronics!


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