Consequences of the Earth rotating faster

Currently, scientists are raising concerns about a phenomenon caused by the Earth rotating faster, since 1972.

The Earth began rotating faster in 1972. Photo: Pixabay .

The Earth is spinning faster this summer. July 10th was the shortest day of the year so far, lasting less than 24 hours by about 1.36 milliseconds, according to data from the International Earth Rotation and Reference Systems Service (IERS) and the U.S. Naval Observatory.

Several other exceptionally short days followed shortly after, on July 22nd and August 5th, predicted to be 1.34 and 1.25 milliseconds shorter than 24 hours, respectively. Scientists believe this phenomenon will have serious long-term consequences and are devoting considerable time to studying it.

Impact of shorter days

The length of a day is measured by the time it takes the Earth to complete one rotation around its axis, which is on average 24 hours or 86,400 seconds. However, in reality, each rotation has slight variations due to many factors, such as the Moon's gravitational pull, seasonal changes in the atmosphere, and the influence of the Earth's liquid core.

The difference is only a few milliseconds, which doesn't affect daily life. But in the long run, this cumulative difference can affect computers, satellites, and telecommunications. Therefore, even the smallest time discrepancies have been monitored by atomic clocks since 1955.

July 5, 2024, was recorded as the shortest day on Earth since the invention of atomic clocks 65 years ago, missing 24 hours by 1.66 milliseconds. Some experts believe this could lead to a scenario similar to the Y2K problem, which once threatened to cripple modern civilization.

An atomic clock in Braunschweig, Germany. Photo: Timeanddate.

“We’ve seen a trend of shorter days since 1972,” said Duncan Agnew, professor emeritus of geophysics at the Scripps Institution of Oceanography . Before 1972, the Earth rotated relatively slowly, leading the IERS to add a “leap second” to UTC (coordinated international time).

Since 1972, a total of 27 leap seconds have been added to UTC, but the rate of additions has slowed down due to the Earth's faster rotation. IERS has not added any leap seconds since 2016.

In 2022, the General Conference on Weights and Measures (CGPM) voted to eliminate leap seconds by 2035, meaning we may never see another leap second. However, if the Earth continues to rotate faster over the next few years, according to Agnew, there is a 40% chance that for the first time ever, a second will need to be removed from UTC time.

Why is the Earth rotating faster?

Agnew said the most significant short-term changes come primarily from the Moon and tides. The Earth rotates more slowly when the Moon is on the equator and more quickly when the satellite is at higher or lower latitudes.

In the summer, the Earth naturally rotates faster, due to the atmosphere slowing down as a result of seasonal changes. According to the physical law of total angular momentum, as the atmosphere slows down, the Earth will rotate faster to compensate. Similarly, over the past 50 years, the Earth's liquid core has also slowed down, causing the solid outer Earth to rotate faster.

The Moon and tides are two reasons why the Earth rotates faster. Photo: NASA.

Meanwhile, climate change is contributing to slowing the Earth's rotation. A study published last year by Agnew showed that melting ice in Antarctica and Greenland is like a figure skater spinning with their arms raised high, but slowing down if they lower their arms along their body. A similar application is occurring with the Earth's rotation.

However, in the long term, if the greenhouse effect continues to increase, its influence will become stronger than the Moon's gravitational pull, according to research from the Swiss Federal Institute of Technology. This would make it difficult to control the length of days in different regions, as well as satellites and GPS.

Judah Levine, a physicist at the National Institute of Standards and Technology (NIST), raised concerns about the possibility of a negative leap second becoming a reality. This is because the hypothesis was previously only included in the standard for completeness. Everyone assumed that simply adding a positive leap second would suffice.

Even with positive leap seconds, after 50 years, many issues remain unresolved. "To this day, some computer systems and telecommunications networks still use the wrong number of seconds, despite repeated use of positive leap seconds," Levine stated, emphasizing the concern that the situation will become even more complicated when leap seconds become negative.

Source: https://znews.vn/he-qua-khi-trai-dat-quay-nhanh-hon-post1570854.html