This summer has gathered the attention of scientists and timers as the Earth rotates faster, making the days marginally smaller.

According to data from the International Systems of Rotation and Reference Systems of the land and the US Naval Observatory, July 22nd is the shorter day of the year So far, which is projected to be 1.34mm of a second of 24 hours. Follows August 5th projected to be even smaller and specifically 1.25mm of a second of 24 hours.

The duration of one day is the time the planet takes to complete a complete rotation around its axis – 24 hours or 86,400 seconds on average. But in fact, every rotation is slightly irregular due to a variety of 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 takes slightly less or slightly more than 86,400 seconds – a second millimeter divergence that has no obvious effect on everyday life.

However these deviations can, in the long run, influence computers, satellites and telecommunications, That is why even the shortest divergences are monitored using individual watches, which were introduced in 1955. Some experts believe that this could lead to a scenario similar to the Y2K problem, which threatened to stop modern culture.

The individual watches They measure the oscillations of people who are kept in a vacuum chamber in the clock itself to calculate 24 hours with maximum accuracy. We call the time of UTC or coordinated world time, which is based on about 450 individual watches and is the global standard for timing, as well as the time at which all our phones and computers are set.

Astronomers also monitor the rotation of the Earth – using satellites that control the position of the planet in relation to the fixed stars, for example – and can detect minimal differences between the time of the individual clocks and the time the Earth actually needs to complete a complete rotation. Last year, on July 5, 2024, the Earth experienced the shortest day ever recorded by the appearance of the individual clock 65 years ago, at 1.66mm of less than 24 hours.

“We are in a trend for slightly faster days since 1972,” said Duncan Agnew, a peer professor of geophysics at the Scripps Oceanography Institute and a Geophysicist researcher at the University of California in San Diego. “But there are fluctuations. It’s like watching the stock market, in fact. There are long -term trends and then there are peaks and falls. “

In 1972, after decades of relatively slow rotation, the rotation of the Earth had accumulated such a delay compared to the individual time that the International Earth Rotation and Reference Systems imposed the addition of a “second second” to UTC. This is similar to the disciple year, which adds an additional day to February every four years to take into account the divergence between the Gregorian calendar and the time the Earth needs to complete a orbit around the sun.

Since 1972, a total of 27 biscuits have been added In the UTC, but the rate of addition has slowed down more and more due to the acceleration of the Earth. Nine two seconds were added throughout the 1970s, and no new disciplines have been added from 2016.

What makes the Earth rotate faster?

Short -term changes In the rotation of the Earth, Agnew said, come from the Moon and the tides, which make it rotate more slowly when the satellite is above the equator and faster when it is at higher or lower altitudes. This phenomenon is exacerbated by the fact that during the summer the Earth is naturally rotating faster – the result of the atmosphere itself slowed down due to seasonal changes, such as the stream of air moving north or south. The laws of physics dictate that the total rotation of the earth and its atmosphere must remain stable, so the speed of rotation lost in the atmosphere is increased by the planet itself. Similarly, in the last 50 years Earth’s wet core has also been slowed down, with the solid land around him accelerating.

By looking at the combination of these effects, scientists can predict if a upcoming day could be particularly short. And a short day may not make any difference, said Levine, the recent trend of shorter days increases the likelihood of a negative second. But the prospect of a negative second raises concerns because there are still problems with positive seconds after 50 years, Judah Levine, a physicist and member of the National Institute of Standards and Technology in dividing time and frequency.

“There are still places that do it wrong or do it at the wrong time, or do it (with) the wrong number, and so on. And this is true of a positive second, which has been done again and again. There is much greater concern for the negative second, because it has never been tested, it has never been tested. ” he said.

The role of the melted ice

Climate change is also a factor that contributes to the issue of seconds, but in an amazing way. While global warming has a significant negative impact on Earth on timing, it has contributed to the neutralization of forces that accelerate the rotation of the land. A study published last year by Agnew in Nature magazine describes in detail how the melting of ice in Antarctica and Greenland spreads over the oceans, slowing the rotation of the Earth.

“If these ice had not melted, if we didn’t have the global warming, then we would already have a negative second jump or we would be very close to having it,” Agnew said. Water melting from the Greenland and Antarctic frosts is responsible for one -third of the global rise of sea level since 1993, according to NASA.

The displacement of this melted ice causes not only changes in the speed of rotation of the Earth, but also on its axis of rotation, according to a research led by Benedikt Soja, Assistant Professor in the Department of Political, Environmental and Geometric Engineer of the Swiss Federal Federal Institute. If global warming continues, its effect can become dominant. “By the end of this century, in a pessimistic scenario (in which people continue to emit more greenhouse gases) the effect of climate change could overcome the influence of the Moon, which in fact guides the rotation of the land over the last billion years,” he said.