Earth rotates faster this summer, making them days marginally smaller and attracting the attention of scientists.
July 10 was shorter day of the year so far, as it lasted 1.36 milliseconds of less than 24 hours, according to data from the international US and Naval Observatory’s rotation and reference systems, which was collected by timeanddate.com.
But today’s day (22.07.2025) is extremely small-the same on August 5-, as it is projected to be 1.34 and 1.25mm of a second less than 24 hours, respectively.
The length of a day is The time the planet takes to complete a complete rotation around its axis -24 hours or 86,400 seconds on average.
In fact, however, each rotation is slightly irregular due to various factors, such as The gravitational attraction of the Moon, the seasonal changes in the atmosphere and the effect of the Earth’s wet core.
As a result, A complete rotation usually lasts slightly less or slightly more than 86,400 seconds – A difference of just millimeters of a second that has no obvious effect on everyday life.
However, these deviations can, in the long run, affect computers, satellites and telecommunications, so even the shortest time deviations are monitored with individual watches, which were introduced in 1955.
What causes faster rotation of the land?
Short -term changes in Earth rotation, Duncan Agnew, a peer professor of geophysics at the SCRIPPS Institute of Oceanography and a Geophysical Researcher at the University of California in San Diego, Diego, CNN. come from the Moon and the tides, which make it rotate more slowly when the satellite It is above the equator and faster when it is at higher or lower altitude.
This phenomenon is combined with the fact that During the summer the land is naturally rotating faster – The result of the slowdown of the atmosphere itself due to seasonal changes, such as moving the jet to the north or south. The laws of physics dictate that the total rotoring of the earth and its atmosphere must remain stable, so the speed of rotation lost from the atmosphere is replaced by the planet itself.
Similarly, In the last 50 years, the wet core of the Earth has slowed, while the solid land is accelerating.
By looking at the combination of these effects, scientists can predict if a upcoming day could be particularly short.
‘These fluctuations have short -term correlations, which means that If the earth accelerates one day, it tends to accelerate the next day, ” said the Judah Levine, Physicist and Associate of the National Institute of Standards and Technology.