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Rare Phenomenon Changes Earth’s Rhythm, Surprises Scientists and May Change Weather Patterns Around the World. Event, Registered in July, Sets a Record in Measuring the Duration of Days on Earth.
The Earth records this Wednesday (09) the shortest day in history, shortened by 1.3 to 1.6 milliseconds due to a slight acceleration in its rotation, influenced by the Moon’s position relative to the Earth’s equator.
This mark surpasses the previous record of July 5, 2024, when the planet “lost” 1.66 ms on the official clock.
Causes of the Shortest Day
Experts from the International Earth Rotation and Reference Systems Service (IERS) explain that the shortest day in history is linked to the gravitational interaction between the Earth and the Moon.
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When the natural satellite reaches its farthest distance from the equator, its gravitational “lever” slightly alters the axis of rotation, shortening the time for a complete turn.
Influence of the Moon on Earth’s Rotation
On July 9, the Moon is near apogee, almost 405,000 km from the surface, and forms the largest possible angle with the equator.
This arrangement mitigates the braking effect normally exerted on the planet and accelerates the rotation enough to create the briefest day on record.
A similar phenomenon is expected to occur on July 22 and August 5, dates for which the IERS projects reductions of up to 1.51 ms in daily duration.
Impacts on Atomic Clocks and Precision Systems
A millisecond is imperceptible in everyday life, but crucial for systems based on atomic time — GPS, satellite communications, electrical grids, and banks rely on synchronization below the microsecond.
Since 1972, scientists have used leap seconds to keep Coordinated Universal Time (UTC) aligned with the Earth’s actual rotation.
If the trend of high speed continues, it may be necessary, for the first time, to subtract a second — the so-called “negative leap second” — possibly in 2029.
Unprecedented Trend in the Planet’s Rotation
From 1960 to 2020, the average rotation had been slowing down due to tides, earthquakes, and mass displacements.
The situation changed in 2020, when “turbo days” emerged, culminating in the record of 2024 and, now, the shortest day in history.
Researchers are investigating whether continental water redistribution, the dynamics of the Earth’s core, or even major seismic events contribute to the briefest day on record in series.
Why This Acceleration Is Notable
“Historically, we expect the Earth to spin slower and slower. Seeing the clock run the other way is extraordinary,” says Leonid Zotov, geophysicist who monitors the length of the day (LOD) at Moscow State University.
Practical Consequences for Society
- Navigation – a 1 ms error in the GPS clock displaces a position by almost 300 m.
- Telecommunications – data centers require accurate timestamps or risk synchronous failures.
- Space Research – tracking missions depend on exact rotation to aim antennas in fractions of a degree.
Precise synchronization ensures that airplanes land at the exact time of their flight plans and that international financial transactions conclude without discrepancies.
Numbers and Records About the Duration of the Day
- Average duration of a day: 86,400 s (24 h).
- Projected shortening today: -1.3 to -1.6 ms.
- Previous record (07/05/2024): -1.66 ms.
- Upcoming critical dates: 07/22 and 08/05/2025.
- Leap seconds applied since 1972: 27 positive, none negative.
What Changes for People’s Routine
Nothing changes in the sense of time — wall clocks do not speed up.
But control centers continuously adjust atomic clocks.
If the shortest day in history repeats, the IERS will call on governments, operators, and tech giants to plan for the first negative second of the digital age.
Curiosities About the Rotation of Planets
Venus takes 243 Earth days to spin once.
Jupiter spins in just 9 h 55 min.
In comparison, millimetric variations of the Earth seem small, but they are enough to redefine global time standards.
What to Expect for the Coming Years
Scientists still do not know if 2025 will inaugurate a phase of faster rotation or if the planet will return to a trend of slowness.
Laser satellite monitoring and VLBI (very long baseline interferometry) networks will track every millisecond lost or gained.
Are you surprised by these invisible adjustments in our planetary clock? Should the acceleration be a cause for concern or merely fascination? Leave your comment on the phenomenon that transformed this July 9 into the briefest day on record for Earth.
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