Earth Spinning Faster In July-August, What Causes It?

YOGYAKARTA - The phenomenon of accelerating Earth's rotation has returned to the attention of scientists this year. Several days in July and August it was recorded that it had a slightly shorter duration than usual.

In general, one standard day on Earth is 24 hours or 86,400 seconds. However, on July 9, July 22, and August 5, scientists expect planetary rotation to be faster relative to the sun so that the duration of the day shortens by one millisecond or more.

Although one standard day on Earth is 86,400 seconds, in fact, the Earth does not always complete one rotation in exactly the same duration. Sometimes the rotation is slightly faster or slower. This difference can reach several milliseconds, very small differences, but significant enough for modern time systems and technologies.

Launching The Guardian, the phenomenon of accelerating Earth's rotation is actually not new. Scientists have recorded this trend since 2020. One of the factors that is believed to play a role is the interaction of gravity between Earth and the Moon.

The moon affects Earth's rotation through a tug-of-war that causes tides of sea water. When the Moon is in a certain position, this drag can slow down or even reduce the effect of the Earth's rotational slowdown. In a certain period, especially when the Moon is far from the equator, this effect weakens and allows Earth's rotation to be slightly faster.

Launching Time, the acceleration of Earth's rotation can also be influenced by events that occur in the earth, one of which is earthquakes. Earthquakes can change the mass distribution within the planet and affect its rotation speed.

In 2005, earthquakes in Indonesia shifted the Earth's pole mass about an inch to the east, reducing the length of the day by 2.68 microseconds. However, no significant earthquakes have occurred recently, so the earthquake is considered not the cause of the current acceleration.

Some scientists also suspect the influence of Earth's core movement, although this still requires further research. Changes in our planet's liquid core can affect Earth's moment of inertia, similar to a skater who turns the body faster when pulling his hand inside.

Although Earth's rotation is faster, this doesn't mean time is literally getting faster for humans. Changes of one to two milliseconds in duration are almost impossible for humans to feel physically. We will still wake up, work, and sleep in the same rhythm.

However, this difference is important for modern technology systems such as GPS, communication networks, banking networks, and satellites. All these systems work with very precise timing synchronization, even up to nanoseconds. Therefore, small differences in Earth's rotation must be accommodated so that the system continues to run smoothly.

"We are sending data very quickly, and everything needs to be time-signed, so computers know which data to deliver," said Dr. David Gozzard, a physicist from the University of Western Australia, quoted from The Guardian.

To maintain the alignment between astronomical time (based on Earth rotation) and atomic time (UTC), scientists have implemented the concept of leap seconds. These additional seconds have been added periodically since 1972 when differences began to feel significant.

However, with the acceleration of Earth's current rotation, it is possible that the world needs to consider reducing leap seconds, something that has never been done before.

Starting in 2035, leap seconds will be halted to avoid the complexity of the global computer system. However, if the rotational acceleration continues, a new approach could be needed to adjust global time.