Planet Earth never stops moving, but Its rotation speed around the axis is experiencing variations unprecedented in recent historyAlthough each day officially has 24 hours, scientists have recently detected that this period can be shortened. in fractions of a millisecond due to a gradual acceleration in rotationIt may sound insignificant, but this phenomenon is being observed and recorded with unprecedented precision thanks to the use of atomic clocks, opening up debate about the causes and consequences of this change for our daily lives.
It's not just a matter of perception or some error in our clocks: The length of the day is perfectly timed, and recent measurements confirm that, since around 2020, the Earth has begun to rotate slightly faster than usual. This acceleration results in slightly shorter days, to the point of reaching historical records for brevity., as is planned to occur on several days in July and August 2025.
What factors are behind the change in the Earth's rotation?
Behind this phenomenon there are numerous factors, both natural and of human origin.On the one hand, the Moon's gravitational influence, especially when it is located at extreme latitudes relative to the equator, can accelerate or slow the planet's spin. Furthermore, the internal movements of the core, the behavior of the oceans, and the atmosphere are also involved in this delicate balance. And, to a lesser extent, the distribution of the Earth's landmass—which depends on both geography and the quantity and distribution of water—can affect the speed of spin.
More recently, An unexpected protagonist has joined the global scene: human infrastructure. NASA has confirmed that the construction of the Three Gorges Dam in China, considered the largest hydroelectric plant in the world, has shifted the Earth's axis of rotation by approximately 2 centimeters. This is due to the colossal mass of water impounded, exceeding 40.000 billion cubic meters, generating a redistribution sufficient to lengthen the day by approximately 0,06 microseconds, although imperceptible to most people.
On the other hand, natural disasters such as major earthquakes, such as the 2004 Indian Ocean tsunami, can slightly accelerate the rotation and thus shorten the day.
Precise measurement: atomic clocks and records for the shortest days
To check these tiny daily changes in day length, Scientists have been using atomic clocks since the 50s., which can measure even thousandths of a second. It has been determined that, for example, On Thursday, June 26, 2025, the day lasted 23 hours, 59 minutes, just fractions of a second less than usual.The prediction is that July 9, July 22, and August 5 could break historical records for brevity due to the combined influence of the Moon and the planet's internal dynamics.
The exact length of each day is published on specialized platforms, and although the variation is minimal (around thousandths of a second), it is essential for synchronizing global systems. That's why there is the so-called LOD (Length of Day), the record that measures the difference from the standard 24 hours.
The role of humanity in the movement of the Earth
For the first time, a work of human engineering is recognized as capable of altering, even slightly, the global mechanics of the planet.. Similar to the effect of a skater changing speed by moving their arms, the way the Earth's landmass moves—whether due to large dams or melting glaciers—influences the speed of rotation. While it was previously thought that only massive natural disasters had a significant impact, we now know that large-scale human activities also factor into the equation. The shift in the Earth's axis following the filling of the Chinese reservoir, although minimal, opens the door to considering how human action can have unforeseen effects on the planet.
The future poses interesting questions, such as whether we will need to change the way we measure time or introduce new adjustments to digital systems to keep them synchronized with the planet's actual rotation.
The future of Earth's rotation: what can we expect?
On the main causes of these changes, Experts stress that the list is complexThe interaction of the Earth's core, ocean water, atmospheric patterns, and the mass moving around the planet cause the planet's rotational speed to fluctuate unpredictably. Researchers are also studying how accelerated melting at the poles could be altering the distribution of mass and, consequently, the shape of the Earth. Astronomical phenomena, such as variations in the lunar orbit, are also contributing to this.
On the other hand, the debate over the use of universal time remains open. Until now, leap seconds have been added to prevent clocks from becoming desynchronized with astronomical time. In the future, it may be questioned whether this system remains the most effective in the face of the acceleration our planet is experiencing.
The study of the Earth's rotation and its recent changes demonstrates the amazing dynamic balance of the planet, where diverse factors such as melting glaciers, human megastructures, and the internal rhythm of the core affect the length of our days. Although these variations are not perceptible on a day-to-day basis, their impact goes beyond science and raises questions about how we will be timing our lives in the near future.
