Recent measurements have revealed that the rotation of Earth’s inner core has slowed down and is now spinning slower than its outer mantle. This is a significant finding that sheds light on the recent changes in the Earth’s magnetic field and the length of day.
The Earth’s solid inner core is situated within the liquid outer core, allowing it to rotate differently from the planet itself. Its spin is driven by the magnetic field generated in the outer core, and it is balanced by gravitational effects within the Earth’s mantle.
Scientists have studied the seismic waves from earthquakes that have passed through the inner core to determine how its spin has changed since the 1960s. The analysis shows that the inner core’s seismic waves have followed a similar path since 2009, indicating that the rotation has paused. A similar occurrence happened in th early 1970s, suggesting that the inner core changes its rotation every few decades.
The study, which is published in Nature Geoscience, offers a better understanding of the interaction between different layers of the Earth and how processes deep inside the planet can affect the surface. The gradual increase in the length of day, adding a fraction of a millisecond each year since 2020, is one of the surface-level effects that can be impacted by changes in the inner core's rotation.
The new findings provide valuable insights into the Earth’s dynamic system and its impact on our planet. Understanding the inner workings of our planet is crucial for predicting and mitigating natural disasters and global phenomena such as climate change.