Undersea internet cables underpin our way of life—but they’re vulnerable, as Red Sea incident shows

The internet is in some ways an abstract layer that augments our physical world, but it’s important to remember that it, too, is physical—a network of networks or, as the late Sen. Ted Stevens memorably described it nearly two decades ago, a “series of tubes.”

Some of the most important data conduits lie buried in the seabed, connecting continents. The vulnerability of these cables was emphasized in late February, when a few were damaged in the Red Sea, markedly degrading people’s online experience in parts of East Africa and South Asia.

At the time, there was speculation that Yemen’s Iran-aligned Houthi rebels had caused the damage after earlier suggesting on social media that the nearby infrastructural hotspot—there are 16 crucial submarine cables in the Red Sea—was a tempting target. The Houthis ultimately denied responsibility, claiming that U.S. and U.K. naval forces were behind the incident.

But now it increasingly looks like the rebels were responsible, albeit unwittingly. Backing up one theory about how the incident played out, Wired yesterday published an analysis that strongly suggests the cables were cut by a sinking cargo ship called the Rubymar, which the Houthis had hit with a ballistic missile. (Attacks such as this one are of course the reason why the U.S. and U.K. have sent naval vessels to the area.)

The evidence isn’t entirely conclusive, but satellite imagery, and data marking the timing of the cables going offline, indicate that the Rubymar’s anchor may have cut or severely bent the fiberoptic cables while dragging along the seabed, as the vessel drifted north from the spot where it was attacked (known as the Gate of Tears). The crew, all of whom were saved, had dropped the anchor during the rescue operation.

If and when the cables are repaired, it should be possible to get a clearer picture of what caused the damage. This would be a dangerous mission, thanks to those Houthi rebels.

The incident serves as a reminder of something positive: the internet’s resilience. The damage to these cables may have had a noticeable impact on connection speeds, but it didn’t cut anyone off. As it’s designed to do, the internet routed around the damage, making sure people’s data packets got where they needed to go.

However, there are limits to this resilience when many cables drop out. Just look at the internet outages in countries like Ivory Coast, Ghana, and Liberia a couple weeks ago, when multiple West African coastal cables failed. In this case, seismic activity is the chief suspect; again, the repair operation will reveal more, as it progresses over the coming weeks.

At this point it’s worth remembering that, last year, Taiwan suspected China's hand behind the severing of two cables that serve its main island. Also last year, Russian hawks threatened to attack Western undersea cables—Russia may or may not have the capacity to actually make good on such threats, but NATO has certainly taken notice, recently establishing a new monitoring station in the U.K. to keep an eye on Russian activity that may point to potential cable sabotage.

After all, that series of tubes has become fundamental to our lives, making it a worthwhile target—and worth defending. More news below.

David Meyer

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This story was originally featured on Fortune.com