The core of the Earth is undergoing surprise structural changes, researchers believe.
A new study has seen scientists unexpectedly find that the inner core of our planet is changing its physical nature.
The changes might have slightly altered the length of each day, researchers believe.
While scientists have long been aware of changes to the Earth’s inner core, most of the research assessing it has looked at the way it rotates. But now scientists have found that other kinds of activity are happening far beneath our feet.
The inner core is found 3,000 mile beneath the surface of the Earth. Gravity keeps it within the molten liquid outer core.
Researchers had begun their work looking to analyse the slowing of the rotation of the inner core. But as they did that work, they found evidence that the inner core is not solid in the way we thought.
That was discovered when scientists looked at seismographs from numerous decades, which chart earthquakes. They showed one that stood out from the rest, and suggested that the inner core is not a solid sphere as thought.
In fact, the core might go through a process known as “viscous deformation”, where its shape changes and it interacts with the outer core.
Researchers were initially confused by the data, which included 121 repeating earthquakes from 42 locations near Antarctica’s South Sandwich Islands. The researchers spotted one set of seismic waves that looked distinct – and, they eventually realised, indicated that there was more physical activity going on in the inner core.
“The molten outer core is widely known to be turbulent, but its turbulence had not been observed to disrupt its neighbor the inner core on a human timescale,” said John Vidale, from the USC Dornsife College of Letters, Arts and Sciences and principal investigator of the study.
“What we’re observing in this study for the first time is likely the outer core disturbing the inner core.”
The work is described in a new paper, ‘Annual-scale variability in both the rotation rate and near surface of Earth’s inner core’, published in the journal Nature Geoscience.
