New evidence suggests the Earth’s inner core no longer rotates faster than the planet’s outer layers
The uncertainty of science: The same scientists who in the late 1990s thought they had detected evidence that the Earth’s inner core rotates faster than the planet’s mantle now say that this faster rotation ceased sometime around 2009.
In 1996, Song and another researcher reported studying earthquakes that originated in the same region over three decades, and whose energy was detected by the same monitoring station thousands of kilometres away. Since the 1960s, the scientists said, the travel time of seismic waves emanating from those earthquakes had changed, indicating that the inner core rotates faster than the planet’s mantle, the layer just beyond the outer core.
…Now, Yang and Song say that the inner core has halted its spin relative to the mantle. They studied earthquakes mostly from between 1995 and 2021, and found that the inner core’s super-rotation had stopped around 2009. They observed the change at various points around the globe, which the researchers say confirms it is a true planet-wide phenomenon related to core rotation, and not just a local change on the inner core’s surface.
It is important to note that there has not been a consensus on this data, that some scientists even doubt the super-rotation ever existed. The data itself is sparse enough and includes enough gaps to allow for this disagreement, which also means this new conclusion is also uncertain.
The uncertainty of science: The same scientists who in the late 1990s thought they had detected evidence that the Earth’s inner core rotates faster than the planet’s mantle now say that this faster rotation ceased sometime around 2009.
In 1996, Song and another researcher reported studying earthquakes that originated in the same region over three decades, and whose energy was detected by the same monitoring station thousands of kilometres away. Since the 1960s, the scientists said, the travel time of seismic waves emanating from those earthquakes had changed, indicating that the inner core rotates faster than the planet’s mantle, the layer just beyond the outer core.
…Now, Yang and Song say that the inner core has halted its spin relative to the mantle. They studied earthquakes mostly from between 1995 and 2021, and found that the inner core’s super-rotation had stopped around 2009. They observed the change at various points around the globe, which the researchers say confirms it is a true planet-wide phenomenon related to core rotation, and not just a local change on the inner core’s surface.
It is important to note that there has not been a consensus on this data, that some scientists even doubt the super-rotation ever existed. The data itself is sparse enough and includes enough gaps to allow for this disagreement, which also means this new conclusion is also uncertain.