Nov 5, 2026 · 53 min
Submarine cables carry the internet beneath our feet
Why Sharks Attack The Internet
The episode reveals how a largely invisible ocean-floor network underpins global communication while creating new security and sensing risks.
- 1Fiber-optic submarine cables carry most international internet traffic, far exceeding satellites in practical importance.
- 2Anchors, fishing gear, deliberate interference, and vulnerable landing points can disrupt communications and expose strategic weaknesses.
- 3The same fibers that transmit data can detect vibrations, turning internet infrastructure into a vast seafloor sensor.
Don't miss
Hannah Fry explains how vibrations in fiber-optic cables can detect activity near the seafloor, turning communications infrastructure into a sensor.
The brief
Hannah Fry and Michael Stevens begin with a deep-sea cable discovery, then examine a physical sample whose small size disguises its global importance.
Most international internet traffic travels through fiber-optic cables rather than satellites, leaving the network exposed to anchors, fishing gear, failures, and deliberate threats.
The cable network is not merely a conduit: vibrations in its fibers can reveal activity near the seafloor, from whales to submarines.
The hosts unpack how wavelength channels and rapid modulation move enormous quantities of data, then turn to Earth’s name, knot theory, and rational superstition.
The episode’s central surprise is that infrastructure built to transmit information can also sense its surroundings, blurring the line between network and instrument.
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