Scientists have recorded the shortest day on Earth since the invention of the atomic clock. According to the International Earth Rotation and Reference Systems Service, on June 29, 2022, the rotation of our planet was 1.59 milliseconds less than the usual 24-hour day. The previous record was recorded on July 19, 2020, when the day decreased by 1.47 milliseconds.
It takes 86,400 seconds for the Earth to make a complete rotation around its axis. In order to establish the exact time of the Earth’s rotation around its axis, atomic clocks are used. This device was first used in the 1950s of the last century.
According to NASA, since 1820, scientists have documented the slowing of the Earth’s rotation. But, according to research, over the past few years, the rotation of the Earth has begun to accelerate, said Dennis McCarthy, director of the U.S. Naval Observatory in Washington.
Why is the speed increasing?
Researchers do not have a definitive answer to how and why the Earth sometimes rotates a little faster. This may be due to glacial isostatic correction or land movement due to melting glaciers, McCarthy explained. According to him, the Earth is wider than the height, which makes its shape look like a flattened spheroid. As a result, glaciers at the poles weigh down the Earth’s crust at the North and South Poles. As the poles melt due to the climate crisis, the pressure on the upper and lower parts of the planet is less, which shifts the crust upwards and makes the Earth rounder, he said. The round shape helps the planet rotate faster: as the Earth gets rounder, its mass gets closer to the center, which increases the speed of rotation, Mcarthy said. This is also a phenomenon used by figure skaters to increase and decrease their rotation speed.
Deleting a speed second
According to McCarthy, since researchers began measuring the Earth’s rotation speed using atomic clocks, the Earth’s rotation speed has been slowing down. In cases where milliseconds accumulate over time, the scientific community adds an extra second to the clock so that it corresponds to the terrestrial one. According to EarthSky, 27 extra seconds have been added since 1972.
“But in the future, due to the acceleration of the Earth’s rotation, one extra second will need to be taken away. If this trend continues, we will have to adjust the time in 3-4 years,” McCarthy said.
Earlier we reported on how GPS uses atomic clocks.
According to CNN
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