According to Time and Date, based on the latest measurements from the National Institute of Standards and Technology (NIST – USA), the first half of 2021 saw time still passing relatively quickly, although it was slower than the “whirlwind year” of 2020. Each day was about 0.39 milliseconds longer than the average day in 2020. From July 1 to September 30, the Earth’s rotation slightly accelerated again, but the days remained 0.05 milliseconds longer compared to 2020.
Earth as seen from space – (Photo: NASA).
At this rate, a “negative leap second” may need to be added to atomic clocks— which currently set the world’s standard time, along with all other types of clocks globally—around 10 years from now. The final decision will rest with the International Earth Rotation and Reference Systems Service (IERS), headquartered in Paris, France.
According to Live Science, the last time this agency decided to adjust the clocks was when a leap second was added at 23:59:59 in 2016.
However, it is also possible that a leap second may not be added in 10 years if the Earth continues to slow down—something that can certainly happen with our planet, which frequently changes its rotational speed.
Previously, in 2020, IERS discovered that the Earth was speeding up, resulting in a day no longer lasting a full 24 hours. The shortest day was July 19, 2020, which was 1.4602 seconds short, prompting calculations for a “negative leap second”, effectively subtracting a second from atomic time.
According to global studies, the phenomenon of the Earth speeding up may be related to climate change. As glaciers melt, the redistribution of mass shifts the planet, causing it to rotate faster on its axis.
