Researchers uncover historical patterns in Earth's rotational deceleration

Researchers uncover historical patterns in Earth's rotational deceleration
by Simon Mansfield
Sydney, Australia (SPX) Aug 15, 2024

Chinese scientists, in collaboration with colleagues from France, Germany, and Ireland, have revealed that from 650 million to 280 million years ago, the Earth-Moon distance expanded by approximately 20,000 kilometers, while the length of a day increased by about 2.2 hours, according to a report from the Science and Technology Daily on Tuesday.

The gradual slowdown of Earth's rotation over time is attributed to tidal dissipation, but the exact rate of this deceleration has been unclear. The recent study, published in the journal 'Proceedings of the National Academy of Sciences' (PNAS), sheds light on this issue.

The research team examined eight geological datasets to reconstruct Earth's rotational history over the period from 650 million to 240 million years ago. Their analysis allowed them to validate physical tidal models and uncover a distinct staircase pattern in the planet's rotational deceleration during the timeframe of 650 million to 280 million years ago.

Notably, the study identified two periods of significant rotational deceleration: from 650 to 500 million years ago and from 350 to 280 million years ago. These intervals were separated by a phase of relative stability in the Earth's rotation from 500 million to 350 million years ago.

The timing of these deceleration periods aligns with critical events in Earth's history, such as the Cambrian explosion and the largest mass extinction event. The researchers suggest that these changes in Earth's rotation may have created conditions that influenced the evolution of early marine ecosystems.

Modeling also suggested that tidal dissipation has been the primary driver of Earth's rotational slowdown, particularly in ancient times.

"The study has important theoretical significance for exploring the climate, environment and biological evolution of the Earth's rotation deceleration," said Ma Chao, a professor at the Chengdu University of Technology.

"The team of researchers will further study the internal links between the Earth's rotation changes and natural phenomena such as the Earth's magnetic field, tidal actions and climate change in order to build a more comprehensive and accurate Earth system evolution model," Ma said.