Earth is spinning faster, new record for shortest day set in June

The Earth completed its shortest day on record in late June, beating the previous record set in 2020.

The report, published on July 27 by the Norwegian time zone tracking website timeanddate.com, said the Earth completed one spin on June 29 in 1.59 milliseconds less than 24 hours.

According to the report, it was Earth's shortest day since scientists began using atomic clocks to measure the planet's rotational speed. The times are based on data provided by the International Earth Rotation and Reference Systems Service.

The planet tends to take a couple of milliseconds or longer to complete one rotation every century, the report adds.

"Within this general pattern, however, the speed of Earth's spin fluctuates," the authors wrote.

"From one day to the next, the time Earth takes to complete one rotation goes up or down by a fraction of a millisecond."

The record comes as the Earth appears to be spinning faster in recent years.

The last record set for shortest day came on July 19, 2020, with the Earth spinning 1.47 milliseconds less than 24 hours. The website also reported 2020 had the 28 shortest days on record since the 1960s.

In 2021, the Earth spun 1.46 milliseconds faster than 24 hours on July 9 for the shortest day of that year.

The report from timeandday.com suspects that the shorter days could be due to the Earth's inner or outer layers, oceans, tides or climate, but so far scientists are unsure.

Other theories include the "Chandler wobble," a phenomenon used to describe the small irregular movements in Earth's geographical poles, timeandday.com said.

The report notes that these faster rotations could result in the introduction of a negative leap second, meaning clocks would skip one second.