Scientists reveal patterns in Earth's rotational deceleration over millions of years

This far infrared photo taken by Tiandu-2 satellite camera on April 8, 2024 shows the Moon and the Earth. BEIJING - Chinese researchers, in collaboration with counterparts from France, Germany and Ireland, have discovered that between 650 million and 280 million years ago, the Earth-Moon distance increased by approximately 20,000 km, and the length of a day extended by roughly 2.2 hours, the Science and Technology Daily reported Tuesday. The researchers analyzed eight geological datasets to reconstruct the Earth's rotational history from 650 million to 240 million years ago. Their findings enabled them to test physical tidal models and identify a staircase pattern in the Earth's deceleration between 650 million and 280 million years ago. Specifically, there are two periods with high Earth rotation deceleration -- from 650 to 500 million years ago and from 350 to 280 million years ago -- separated by an interval of stalled deceleration from 500 million to 350 million years ago.