Reader · no content
No body text on file.
Open the original to read the full piece.
Samanth Subramanian on the Undersea Cables That Keep the Internet Alive
Brief
Undersea fiber‑optic cables are the physical backbone of the global Internet—thin, glass fibers that carry laser light across oceans—yet their manufacture, routing and repair are shaped by engineering limits, economics and geopolitics. In the episode Tracy Alloway and Jill Wisenthal interview Samanth Subramanian, author of The Web Beneath the Waves, who traces the technology from Victorian telegraphy to today’s hair‑thin fiber using wavelength‑division multiplexing. Subramanian details how cables are surveyed, spooled onto laying ships, and carefully deployed (speed matters to avoid snap or slack) and how repairs still rely on grapnel hooks to recover broken cable followed by delicate on‑board splicing in clean‑room labs.
The conversation moves from technique to power: ownership and financing have shifted from state telecom consortiums in the 1980s–90s to investor projects in the 2000s and now to hyperscalers. Subramanian says roughly two thirds of new cables are funded by Google, Meta, Amazon or Microsoft, with transatlantic builds costing around US$500 million—altering who chooses landing sites and raising questions about data control. He highlights concrete vulnerabilities: chokepoints such as Egypt/Suez and the Strait of Hormuz concentrate traffic; about 500–550 cables exist worldwide and ~100 cuts happen annually (mostly accidents), yet built‑in redundancy mitigates most outages. The Tonga example—where a volcanic underwater landslide severed the island’s only international cable—illustrates how societies can be plunged into temporary connectivity blackout. The interviewers and guest agree that satellites (e.g., Starlink) are useful stopgaps but cannot replace the enormous capacity that submarine fiber provides. Finally, Subramanian outlines geopolitical risks—sanctions affecting Chinese firms (HMN/Huawei), fears of Internet bifurcation, and the military’s separate cable systems—leaving listeners with the sense that the Internet’s physical reality is both robust and fragile, shaped by engineering, money and international politics.
Why it matters
Samanth Subramanian (author of The Web Beneath the Waves) explained that modern undersea fiber‑optic cores can be as thin as a human hair and carry multiple data streams using wavelength‑division multiplexing (WDM), sending different light frequencies down a single fiber (Speaker 3).
Key details
- There are roughly 500–550 active undersea cables worldwide and about 100 cable cuts occur each year (mostly accidental), but redundancy in the network usually prevents large scale outages (Speaker 3).
- Ownership shifted over decades: 1980s–90s state telecom consortiums gave way to investor‑led projects in the 2000s, and in the last ~7–8 years the biggest tech companies (Google, Meta, Amazon, Microsoft) fund roughly two out of every three new cables—changing who decides routes and landing points (Speaker 3).
- A single transatlantic cable build today costs in the order of US$500 million (example given for a London–New York route), which is why hyperscalers finance many projects themselves (Speaker 3).
- Geography and chokepoints matter: Egypt (Suez region), the Strait of Hormuz and the Red Sea concentrate cables and are strategic vulnerabilities; Tonga’s loss of its sole international cable after a volcanic underwater landslide was used as a case study of what temporary detachment from the global Internet looks like (Speaker 3).
- Repair and protection are old‑school and high‑tech hybrids: ships lay and retrieve cable from spools; repairs often use grapnel hooks to snag breaks, then on‑board clean rooms and splicing labs rejoin fiber. Governments have increased naval and coast guard protection and militaries run their own private cables (Speaker 3).