The last June 29Earth set an unusual record: It had its shortest day since the 1960s, when scientists began measuring the planet’s rotation with highly accurate atomic clocks.
As you know, in general terms, the earth completes one complete revolution on its axis every 24 hours. That single turn symbolizes a day: the cycle of day and night.
But June 29 was the exception: according to a note in the British newspaper, midnight came 1.59 milliseconds earlier than expected. Guardian,
In recent years, shorter days have become more and more frequent.
In 2020, Earth had 28 of the shortest days in the past 50 years, with the shortest day, July 19, shaving 1.47 milliseconds out of the 86,400 seconds that make up 24 hours.
The record of June 29 was about to be broken again last month, because 26 July This was 1.5 milliseconds less than usual.
a speed out of the ordinary
british daily Wire adds that, for his part, Earth’s average rotational speed usually decreases little over time.
In fact, scientists have been forced to add 27 leap seconds to atomic time since the 1970s as the planet has slowed.
But since 2020, the phenomenon has reversed: speed records were often broken in the past two years.
“Although the effect is too small for humans to notice, it can build up over time, affecting modern satellite navigation and communications systems that are timed to conform to the traditional position of the Sun, Moon and stars. depend”, says the newspaper.
origin of this speed of rotation
Scientists attribute the increase in Earth’s rotation speed to a phenomenon called the “Chadler wobble”. The motion is constantly changing due to the complex motion of its nucleus, oceans and atmosphere, as well as the influence of celestial bodies such as the Moon.
The speed of the planet’s rotation on its axis varies daily due to tidal friction and the varying distance between the Earth and the Moon.
The “Chandler wobble” is the change in the Earth’s spin on its axis and causes an increase in Earth’s rotation in general, meaning that it takes longer to complete one spin. But spin has faltered less in recent years.
Leonid Zotov of the Sternberg Astronomical Institute at Lomonosov Moscow State University believes that the lack of oscillation may be behind the fast days as reported. Wire.
