The Earth’s inner core appears to have slowed its rotation and it may be reversing its spin, according to a new study published in the journal Nature Geoscience. (Sergei Korsakov, Roscosmos State Space Corporation via AP, File)
Earth’s inner core, a red-hot ball of iron 1,800 miles below our feet, stopped spinning recently, and it may now be reversing directions, according to an analysis of seismic activity.
The discovery indicates that the Earth’s center regularly pauses and reverses its rotation, researchers in China wrote in a study published Jan. 23 in the journal Nature Geoscience.
“We show surprising observations that indicate the inner core has nearly ceased its rotation in the recent decade and may be experiencing a turning back in a multidecadal oscillation, with another turning point in the early 1970s,” Dr. Yi Yang and Dr. Xiaodong Song, scientists at Peking University, wrote in the study.
Just as the Earth spins, the planet’s inner core turns, though not necessarily at the same speed, and some research indicates the core moves faster, according to the National Science Foundation. The inner core can spin independently because it is encased in a liquid outer core, similar to an egg yolk inside the more fluid egg white.
By analyzing earthquake data from across the globe over the last 28 years, researchers confirmed that the inner core’s rotation relative to the Earth’s mantle — the bulk of the planet’s interior between the core and the outer crust — had ceased around 2009, according to a story about the study in Nature Geoscience.
Additionally, their findings suggests the inner core may be in the process of reversing the direction of its spin, leading researchers to hypothesize a pattern.
“We infer the inner core rotation changes direction every 35 years,” Dr. Song told McClatchy News.
Why exactly this phenomenon occurs is not clear to researchers. The gravitational and magnetic forces that factor into the inner core’s movement are likely partly responsible, they said.
Importantly, their findings also imply a strong connection between the crust, the thin surface slice that we inhabit, and the deepest parts of the globe, researchers said.
The core’s multi-decade rotational pattern “coincides with several important geophysical observations,” researchers wrote, including changes in the magnetic field and the length of the day, meaning the inner workings of the planet could impact the duration of our days.
Still, we have no reason to be concerned, as these changes will not be noticeable to us, researchers said.
“The phenomenon does not affect our daily lives,” Dr. Song said.
Though more research is needed, these results represent another step in the process of unraveling the complex mechanisms of the inner Earth, an untraversable inferno that remains very difficult to study.