The Earth Is Spinning Faster—Here's Why July and August Will Have Record-Short Days
From the point of view of the sun, it takes Earth roughly 86,400 seconds (24 hours) to complete one full rotation. This changes slightly from day to day, and these small variations are measured with atomic clocks. The number of milliseconds above or below 86,400 seconds is referred to as length of day.
Until 2020, the shortest length of day ever recorded was -1.05 milliseconds, meaning it took the Earth 1.05 milliseconds less than 86,400 seconds to complete one rotation. Since then, Earth has beaten this record every year, with the shortest day of all being -1.66 milliseconds.
This month,TimeandDate reports that Earth will get close to its previous record. On July 9, the length of date is expected to be -1.30 milliseconds, followed by -1.38 milliseconds on July 22 and -1.51 milliseconds on August 5.
"Nobody expected this," Leonid Zotov, a leading authority on Earth rotation at Moscow State University, told the outlet. "The cause of this acceleration is not explained." Zotov added that most scientists believe it is something inside the Earth. "Ocean and atmospheric models don't explain this huge acceleration," he said.
Despite this acceleration, Zotov predicts that Earth will slow down soon. "I think we have reached the minimum," he told TimeandDate. "Sooner or later, Earth will decelerate." In the meantime, scientists will continue to study the reason behind Earth's length of day variations.
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