Researchers have reported that in the coming weeks, the Earth will rotate faster, affecting the length of some days. Unbeknownst to us, July 9 was also a shorter day. The same is expected for July 22 and August 5, which will be shortened by 1.3 to 1.51 milliseconds due to the anticipated influence of the Moon’s position on Earth’s rotation.
A day on Earth lasts 24 hours, or 86,400 seconds. That’s how long it takes our planet to complete a full rotation on its axis. However, this process is influenced by a number of factors, including the positions of the Sun and Moon, changes in Earth’s magnetic field, and the movement (balance) of mass on the surface of our planet.
Since the dawn of Earth, its rotation has gradually slowed down, resulting in longer days. Researchers have found that 1 to 2 billion years ago, a day on Earth lasted only 19 hours. This is likely related to the Moon being closer to our planet, which intensified its gravitational pull and caused Earth to spin faster.
Since then, as the Moon has drifted away from us, the average length of a day has increased. However, in recent years, scientists have observed changes in Earth’s rotation. In 2020, they noted that Earth is spinning faster than it has since observations began in the 1970s.
On July 5, 2024, scientists recorded the shortest day in the history of observations. According to data from timeanddate.com, it was shorter by 1.66 milliseconds.
On July 22 and August 5, 2025, the Moon will be at its maximum distance from Earth’s equator, which will alter the gravitational influence on our planet’s axis. (The same occurred on July 9).
Imagine Earth as a spinning top. If you hold it by the middle and give it a spin, it will rotate more slowly than if you hold it by the top and bottom.
As the Moon approaches the poles, the rotation of our planet speeds up, making the day shorter than usual.
Human Impact and Other Factors
These changes are expected. However, recent studies have shown that human activity is also causing changes in the planet’s rotation. NASA calculated that the movement of ice and groundwater associated with the climate crisis has increased the length of our day by 1.33 milliseconds per century from 2000 to 2018.
Earth’s rotation can also be altered by certain events. For instance, the 2011 earthquake in Japan shortened the length of the day by 1.8 microseconds. Even seasonal changes affect Earth’s rotation, reported Richard Holme, a geophysicist at the University of Liverpool (UK).
“In the Northern Hemisphere, there is more land than in the Southern Hemisphere. In the summer, trees in the north are covered with leaves, which means that mass is moving to the surface—further from the Earth’s axis of rotation,” Holme explained to Live Science. The speed of rotation of any moving body depends on the distribution of mass. As the mass of the Earth moves away from the core in the summer, its rotation slows down, resulting in longer days, Holme clarified.
Of course, our clocks still show 24 hours. We don’t feel this difference. According to the expert, a change in time zones could only occur if the day increases by 900 milliseconds (0.9 seconds).