The Invisible Clock That Runs the Entire World

Episode 11  ·  Who decides what time it is: atomic clocks, Coordinated Universal Time, leap seconds and the second of the future  ·  all sources

In December 2025, winds of more than 100 mph cut the power in Boulder, Colorado. At the government lab there, a backup generator failed, and the atomic clocks that keep official time for the United States lost their link to the servers that share it. Their time drifted by about four millionths of a second. This film explains who decides what time it is: how the second is defined by caesium atoms, how about 450 atomic clocks in some 85 labs are averaged once a month near Paris into Coordinated Universal Time (UTC), how that time reaches power grids, traders, GPS, the internet and phone masts, and why leap seconds are being stopped.

This is a fully animated film. Every visual was drawn for ColdProvenance; no footage, photographs or recordings are used. Narration is a synthesized voice. The music and sound effects were created for this film. Every factual claim is sourced below.

Sources

• The Boulder outage of December 2025: The Register, Jeff Geerling and Denver7: the high winds and power cuts, the failed backup generator, NIST's warning that its Boulder time servers could not be trusted, and a drift of about four to five microseconds
• BIPM — Time metrology and Circular T; Panfilo and Arias, The Coordinated Universal Time (UTC), Metrologia (2019): about 450 atomic clocks in about 85 labs, compared mostly by satellite, UTC worked out once a month at Sèvres near Paris, the published offset of each lab
• NIST — How is UTC(NIST) related to Coordinated Universal Time (UTC): each lab's real-time copy of UTC, steered to stay close to it; GPS time traceable to UTC
• The SI Brochure (BIPM) and the CCTF Roadmap towards the redefinition of the second, Metrologia (2024): the caesium definition of the second since 1967 (9,192,631,770 cycles), optical clocks about 100 times more precise, a possible redefinition around 2030
• NIST — NIST's Internet Time Service Serves the World (March 2016): about 16 billion requests a day
• Timing requirements: the EU MiFID II rules (RTS 25) for high-frequency trading, via the NPL time services brochure (100 microseconds of UTC); the NASPI Time Synchronization in the Electric Power System report (PNNL, 2017) for grid measurements to about a microsecond; 4G/5G network timing of about 1.5 microseconds
• IERS and BIPM: leap seconds since 1972 to keep UTC within 0.9 s of the Earth's rotation; 27 added, the last at the end of 2016
• The leap second of 30 June 2012: iTnews and IEEE Spectrum: the booking-system outage, check-in by hand and more than 400 delayed Qantas flights
• Cloudflare — How and why the leap second affected Cloudflare DNS (January 2017): code that assumed time could never run backwards
• Agnew — A global timekeeping problem postponed by global warming, Nature 628 (2024): the faster spin, a possible minute of 59 seconds, and melting polar ice pushing the need back from about 2026 to about 2029
• BIPM — Resolution 4 of the 27th CGPM (2022): leap seconds to stop by 2035; the draft resolution for the October 2026 meeting, as reported by lunartime.org, proposing an end from 2027

Visuals

• All animation, buildings, clocks, satellites, Earth and diagrams were created by ColdProvenance for this film. No footage or photographs appear in this film.
• The lab buildings, the bureau's house near Paris, the airport and the city scenes are simplified illustrations, not exact views. The skater is an illustrative figure.
• Sizes, distances and time scales are not to scale where marked. The ring of 60 seconds, the drifting light on the dial and the year road are visual metaphors; their numbers are the sourced figures.
• Coastlines: Natural Earth Public domain, via world-atlas.

Audio

• Narration: synthesized voice.
• Music, ambience and sound effects: created for this film. No stock music, sound libraries or field recordings are used.