Undersea Internet Cables
The 700,000 miles of cables connecting the world's internet
Where this idea comes from
Start here — these are the sources that inspired this exploration.
Introduction
Virtually all international internet traffic travels through over 700,000 nautical miles of undersea fiber-optic cables lying on the ocean floor. These cables connect continents, carrying emails, video calls, web pages, and streaming content. Companies like Arelion operate networks spanning 77,000 km connecting Europe, North America, and Asia. The design and routing of this infrastructure involves real mathematical problems: finding shortest paths between landing points, ensuring network redundancy so a single cable cut does not disconnect regions, and optimizing data routing across the network. This is graph theory in action on a global scale. Graph theory here (syllabus topics 3.14 to 3.16) is AI HL content, so if you are doing AI SL or an AA course, treat this as an extension beyond your normal syllabus.
Guiding Questions
- How can the global cable network be represented as a graph?
- What's the shortest cable route between New York and Tokyo?
- How many cable cuts would disconnect a major region?
- Model a handful of landing points as your own weighted graph. Find its minimum spanning tree — what would the network cost with no redundancy at all?
- Real cable networks build in extra routes beyond the minimum spanning tree on purpose. Compare your minimum spanning tree with a real map of the cables (or a more redundant version of your own), and count how many extra edges are added, and why.