At a Glance
- Scientists have discovered that Earth’s inner core is slowing down relative to its surface, a significant change in its movement pattern.
- The study provides evidence that the inner core’s speed decreased around 2010, contrary to previous beliefs that it rotates faster than the Earth’s surface.
- The inner core, a solid iron-nickel sphere, is studied through earthquake seismic waves despite being more than 3,000 miles beneath the Earth’s surface.
- Researchers tracked the inner core’s detailed movements by analyzing seismic data from repeating earthquakes near the South Sandwich Islands.
- The inner core’s altered movement could subtly affect Earth’s geophysical processes, including potentially changing the length of a day by fractions of a second.
Recent research by scientists at the University of Southern California (USC) has unveiled a significant discovery about the Earth’s inner core. Published in Nature, the study confirms that the inner core is slowing down about the planet’s surface, marking a notable change in its movement pattern.
For the past two decades, the scientific community has been divided on the inner core’s rotational behavior, with previous studies suggesting it rotates faster than the Earth’s surface. However, the USC study, led by John Vidale, Dean’s Professor of Earth Sciences, provides compelling evidence that the inner core decreased its speed around 2010, moving at a slower pace than the Earth’s surface.
The inner core, a solid iron-nickel sphere more than 3,000 miles beneath the Earth’s surface, is surrounded by the liquid outer core. Researchers rely on earthquake seismic waves to study the inner core’s movements despite its inaccessible nature. By analyzing seismic data from repeating earthquakes around the South Sandwich Islands, Vidale and his team could track the inner core’s progression and regression with unprecedented detail.
The implications of the inner core’s altered movement remain a subject of ongoing research. Vidale suggests that this change may have subtle effects on Earth, potentially impacting the length of a day by fractions of a second. As scientists delve deeper into understanding the dynamics of the inner core, they aim to unravel the intricate relationship between the core’s movements and Earth’s overall geophysical processes.
References
- Kwong, W. & University of Southern California. (2024, June 12). Study confirms the rotation of Earth’s inner core has slowed. Phys.Org; University of Southern California. https://phys.org/news/2024-06-rotation-earth-core.html
- Wang, W., Vidale, J. E., Pang, G., Koper, K. D., & Wang, R. (2024). Inner core backtracking by seismic waveform change reversals. Nature, 1–4. https://doi.org/10.1038/s41586-024-07536-4
