The Acceleration of Earth’s Rotation: A Record-Breaking Phenomenon
If you feel that days are getting shorter, it might be because our planet has stepped on the accelerator . Since 2020, the Earth has been spinning on its axis at a slightly higher speed than usual, setting records that have intrigued scientists. Astronomers are still investigating the reasons behind this phenomenon, and predictions suggest that the next record could occur in just a few days.
The shortest documented day. Astrophysicist Graham Jones predicts three key dates in 2025 when the Earth could experience its fastest rotation since we began recording such data: July 9 , July 22 , or August 5 , 2025.
Any of these dates could set the Earth closer to or beyond the previous record established on July 5, 2024 . However, other experts remain skeptical, suggesting that this year’s shortest day may still linger a few milliseconds behind last year’s record.
An anomaly of milliseconds. A solar day is typically defined as lasting 86,400 seconds ; that is, 24 hours . However, various minute fluctuations in the Earth’s rotation result in days that are ever-so-slightly longer or shorter. These variations, often measured in milliseconds, are precisely tracked thanks to advanced atomic clocks .
Before 2020, the shortest day on record fell short of 24 hours by 1.05 milliseconds . Yet since that time, we have consistently broken this threshold. In 2021, the shortest day was 24 hours – 1.47 ms ; in 2022, it dropped further to 24 hours −1.59 ms ; in 2023, it rose to 24 hours −1.31 ms , and currently, 2024 has marked yet another record with 24 hours – 1.66 ms .
Why this summer. The anticipated dates in 2025 coincide with moments when the Moon’s orbit positions it at its farthest point from the Earth’s equator. While this lunar position does influence the Earth’s rotation speed, it doesn’t account for the mysterious acceleration we’ve seen recently, which remains largely unexplained.
The intriguing aspect of this acceleration is its contradiction to historical trends. For billions of years , the Moon has had a braking effect on Earth’s rotation rate. Initially, roughly 4.5 billion years ago , a day on Earth lasted between three to six hours due to the gravitational pull of the Moon, which influences the tides. This constant friction with the oceans has gradually robbed the Earth of its angular momentum , slowing its spin.
No one expected this acceleration. Scientists often rely on models that consider various factors, including ocean currents and atmospheric movements, to explain the Earth’s rotational speed. However, these models fall short when it comes to accounting for the recent uptick in speed. Current hypotheses propose complex, yet poorly understood, processes occurring in the Earth’s core that may be altering its rotational dynamics.
If the current trend of acceleration persists without interruption, experts indicate that in about 50,000 million years , Earth’s rotation could become synchronized with the Moon’s orbit. This synchronization would result in a phenomenon called “tide blocking,” meaning that one side of Earth would perpetually face the Moon, rendering the satellite visible only from the planet’s midpoint. Fortunately, this is a distant concern; in about 10,000 million years , our Sun will transition into a white dwarf , and Earth will likely be uninhabitable by then.
In summary, the increasing speed of Earth’s rotation presents a fascinating conundrum that challenges existing scientific paradigms. It intertwines the realms of geology, astronomy, and physics, reminding us of the intricate and ever-changing nature of our planet. As researchers continue to uncover the mysteries behind this acceleration, it opens new avenues of understanding the dynamics shaping our world and its future.