The first systems to fail are the ones modern civilization most invisibly depends on. GPS depends on radio signals from satellites at about 11,000 miles altitude; at 3 miles per second, those signals would take about 70 minutes one way. Geostationary weather satellites at 22,236 miles—including the GOES family that provides continuous atmospheric monitoring—would be working with a one-way delay of just over two hours, eliminating real-time storm tracking. Radar fares no better, because the FAA defines radar as radio-wave time-of-flight: a target 300 miles away would return a radar echo in about 200 seconds, or more than three minutes. Missile-warning systems and geostationary infrared satellites such as DSP and SBIRS are built to detect launches and deliver timely first-alert data; in a slow-light cage, their value collapses from warning to belated archaeology.
Telecommunications implode next. The ITU says submarine cables carry roughly 99% of the world’s Internet traffic, and NIST’s analysis of critical infrastructure timing shows telecommunications—especially mobile networks—depend heavily on precise synchronization, with some standards requiring timing on the order of 1 to 10 microseconds and explicitly relying on GPS-disciplined clocks. Under the new rule, a 1 km radio path takes about 0.207 seconds, or about 207,000 microseconds—orders of magnitude beyond the tolerance of modern cellular timing. In story terms, cellphone service does not merely become “bad.” It becomes structurally nonviable. The internet does not vanish, but it stops being real-time; it becomes an electrical mail system with catastrophic lag, broken authentication, and shattered cloud dependence.
Computers fail for a more subtle and more frightening reason: information inside them is physical too. NIST notes that measurable propagation delay exists in electrical transmission lines and optical fibers, and a UCSB teaching demonstration pegs signal speed in coaxial cable at about two-thirds of vacuum c. If that scales down with the new cap, then even a six-inch trace carries a delay of about 47 microseconds, pushing present-day high-speed electronics out of the gigahertz world and into a grotesquely slower regime. The result is not necessarily exploding hardware; it is something more unsettling: hardware that remains intact but is functionally unusable for the civilization built around it. Operating systems stall. Datacenters hang. Real-time AI inference becomes glacial. Everything “smart” becomes stupid by physics.
Power systems become one of the film’s most original and realistic horrors. NIST calls the grid the most critical of critical infrastructures and documents the dependence of newer wide-area monitoring on GPS-timed phasor measurement units. DOE explains that synchrophasors stream timestamped measurements across communications networks so operators can align distant readings in real time. But if a 60 Hz electromagnetic wave propagates at only 3 miles per second, its wavelength is only about 80 meters. That makes continent-scale synchronized AC transmission a phase catastrophe. The plausible survivor topology is not a national grid but fragmented local islands: neighborhood microgrids, hydro plants in isolation, diesel backup networks, hand-operated substations, and brutal rationing.
Finance becomes untrustworthy before it becomes impossible. NIST’s stock-exchange section notes that modern exchanges and automated platforms are deeply timing-dependent, that high-frequency trading executes in microsecond intervals, and that exchanges routinely use GPS-derived time inside data centers. In a slow-light event, markets freeze not only because latency becomes absurd, but because causality in trade ordering becomes politically contestable. No one can prove whose packet or order came first across a broken planet. Payment rails seize, banking trust evaporates, and physical cash returns with startling speed.
Hospitals and medicine do not fail all at once; they fail in layers. A 2025 National Academies workshop summary on health-care critical infrastructure emphasizes that hospitals depend on energy, IT systems, communications, supply chains, water, and workforce as interdependent sectors. That is exactly the correct model for Protobound. A ventilator in one room may still function. A surgeon can still cut. A local infusion pump can still run. But elevators stall, cloud-based records vanish, blood deliveries miss their windows, pharmacies cannot verify stock, remote consults die, and regional hospital load balancing collapses. Medicine becomes physically possible and systemically broken at the same time, which is much more terrifying on screen than a simple blackout.
The film should be equally precise about what still works. FAA guidance on GPS outages shows that aviation still retains non-GPS fallbacks such as VOR and ILS, at least in principle, and NIST notes that the pre-GPS parts of the grid did operate before modern timing systems—just with far less efficiency and situational awareness. That gives the movie its survival logic: local, analog, manual, and short-distance systems endure longest. The visual rule is beautifully simple. At the new limit, light takes about 0.63 milliseconds to cross 10 feet, about 63 milliseconds to cross 1,000 feet, and about 0.33 seconds to cross one mile. So people are not blind indoors. But cities become uncanny. Lightning crawls. Explosions bloom before their own glow reaches distant observers. Reflections feel wrong. Skies edit themselves in public.