There’s a lot to worry about in the world today, so apologies in advance for this additional level of existential stress: New research indicates that in the event of a solar superstorm—the kind that hit in 1859—the internet could go down entirely, and take even longer than the power grid to restore. The risk lies primarily in the undersea cables that connect continents, which are inconsistently grounded and rely on components that a geomagnetic surge could disrupt. While solar storms of that magnitude are rare, they do happen—and internet infrastructure has never been tested against it.