The Earth’s rotation is predicted to be 1.34 milliseconds shorter than usual tomorrow on July 22. Scientists are puzzled by the recent increase in speed, which contradicts long-term predictions of a slowing down rotation.
The Earth’s rotation has altered significantly over time, with the length of day varying from around 490 to 372 days in Earth’s history. The Moon is thought to be responsible for the long-term slowing of the Earth’s rotation, but it can also cause acceleration when closer to the equator.
Recent years have seen a reversal of this trend, with the shortest days since 1960 recorded in 2020 and each year thereafter breaking the record. However, scientists are unsure why this sudden change occurred.
Astronomers predict that July 22 will be one of the shortest days of the year due to the Moon’s maximum distance from the Earth’s equator. The trend is unexpected, with only 27 leap seconds added since 1972, and no leap second expected in June.
Experts point to internal factors within the Earth, such as ocean and atmospheric models not explaining the acceleration, and earthquakes as possible causes. A magnitude 9.0 earthquake off Japan’s east coast shifted the Earth’s axis by about 17 centimeters, speeding up its rotation by 1.8 microseconds.
The IERS will continue to monitor the Earth’s rotation, providing further updates on the shortened days in July and August.
Source: https://www.iflscience.com/earths-rotation-will-speed-up-tomorrow-set-to-make-the-day-134-milliseconds-shorter-80093