Al Jazeera – Riyadh:
Planet Earth recorded its shortest day since records began, lasting 1.59 milliseconds of its usual 24-hour rotation on June 29, raising the possibility of a leap second to keep clocks consistent, and this is the first time global clocks have been accelerated.
The Earth’s rotation is known to be slowing down, taking 27 leap seconds to maintain atomic time since the 1970s. The most recent was on New Year’s Eve 2016, when the clocks paused for a second to allow the Earth to catch up. But since 2020, the phenomenon has reversed – the previous day’s fastest was 1.47 milliseconds on July 19 of that year.
The change cannot be detected by humans, but it can affect satellites and navigation systems, and experts say Chandler and Bobble – a change in the Earth’s rotation on its axis – may be the cause.
“The amplitude of the natural oscillation is regarding four meters at the Earth’s surface, but it disappeared from 2017 to 2020,” said Dr. Leonid Zotov of the Sternberg Institute of Astronomy in Moscow.
Other factors that can influence the length of Earth’s days include the accumulation of snow on mountains in the northern hemisphere in the winter and then melting in the summer. Global warming is also thought to have an effect by melting ice and snow at a faster rate.
The International Earth Rotation Service in Paris monitors the planet’s rotation and will tell countries when leap seconds should be added or removed, with six months’ notice.
