- Earth's rotation has sped up, shortening some days by over a millisecond this summer
- A negative leap second, subtracting one second from UTC, may be introduced for the first time
- Since 1972, 27 positive leap seconds have been added, but none have been subtracted before
In a rare and unprecedented move, scientists and world timekeepers are considering reducing one second from Coordinated Universal Time (UTC) as Earth's rotation speeds up.
The most recent data indicates that Earth's rotation is somewhat faster this summer, with some days measuring more than a millisecond shorter than a typical 24-hour period, CNN reported.
Even the slightest change in the planet's rotation over time can cause sensitive systems, such as satellites, GPS, and international communications networks, to malfunction.
This hypothetical "negative leap second" will be the first in history.
The International Earth Rotation and Reference Systems Service and the US Naval Observatory declared that July 10 was the shortest day of the year so far, lasting 1.36 milliseconds less than 24 hours, as per Time And Date.
Earth's rotation has been progressively slowing down for decades as a result of the moon's tidal friction. Recent astronomical data and atomic clock observations, however, indicate that the Earth is currently spinning faster than it did previously.
The earth takes 24 hours, or an average of 86,400 seconds, to complete one full rotation on its axis, which is equivalent to a day. In reality, however, each rotation is somewhat erratic because of several variables, including the moon's gravitational pull and the impact of the Earth's liquid core.
What is the concern now?
The official timekeepers in the world may have to take an unprecedented step if this pace keeps up; deduct one complete second from the world time.
Since 1972, so-called "leap seconds" have been added 27 times to compensate for Earth's rather erratic rotation. However, there has never been the use of a negative "leap second," which will essentially accelerate the UTC by one second.
There is now a 40 per cent likelihood that it will occur by 2035, according to experts.
Why is the Earth spinning faster?
The causes of Earth's fluctuating rotation are multifaceted. Seasonal fluctuations in the atmosphere, the moon's gravitational influence, and even the shifting motion of the Earth's molten core all contribute.
The moon and tides cause the shortest-term variations in Earth's rotation, according to experts, making it spin faster when the satellite is at higher or lower altitudes and slower when it is above the equator.
Another factor is climate change. Greenland and Antarctica's melting ice redistributes mass around the Earth, slowing its rotation and possibly preserving time before a global time reset becomes inevitable.
Research geophysicist Duncan Agnew of the University of California, San Diego, compared it to observing the stock market, and said, "There are long-term trends, and then there are peaks and falls."
