The very deep center of the planet, a solid ball of iron and nickel floating in a sea of molten rock, appears to be slowing down relative to the motion of the Earth itself. The inner core slowed down so much that it practically went into reverse, according to the Los Angeles Times.
The rotation of the Earth’s inner core has slowed considerably PHOTO Archive
The discovery, made by geophysicist John Vidale and his colleague Wei Wang of the Chinese Academy of Sciences and recently published in the journal Nature, provides the most compelling evidence yet that the core appears to operate with a mind of its own.
“It might oscillate back and forth, but it might also be on a random path. It went in one direction for a while, then it turns in the other direction. Who knows what he will do next”Vidale said
Life on the surface is unaffected…for now
Fluctuations happening 3,000 miles below us won’t affect life on the planet’s surface in a noticeable way, at least for now, Vidale said.
“There’s virtually no effect on humans, as far as I’ve seen. It is part of understanding the evolution of the planet. What we would like to know in more detail is what are the forces that move the inner core,” the researcher also said.
Scientists had their first inkling that the inner core was moving in the 1990s, he said. It took years to support that theory with hard evidence, mainly because of the difficulty of studying a mass so far away—and suspended in a hellish sea of liquid iron with temperatures ranging from 8,000 to 10,000 degrees.
Instead, Vidale, who was director of the Southern California Earthquake Center at USC from 2017 to 2018, looked inside the planet by tracking seismic waves from earthquakes that occurred at the southern tip of South America. As the waves passed through the heart of the planet, they were recorded by 400 seismometers positioned at the other end of the globe, in Alaska and northern Canada. The sensors were of the same type used to measure ground vibrations during nuclear tests.
“People thought the planet was empty”
He compared those refined readings to earthquake signals recorded in previous years to see where they fit. That’s how he determined that the rotation has decreased since 2010. Before that, the rotation of the core had accelerated.
The findings add to the mystery of the most unfathomable part of our world, Vidale said. Literature and myths related to the Earth’s core filled the void of knowledge with all kinds of fanciful ideas.
“I’m not much of a philosopher, but we’ve all had nightmares about what goes on inside the planet”Vidale said. “Just a few hundred years ago, people thought the planet was empty and that people lived there. It’s pretty exotic — exotic like Jupiter, but it’s right under our feet.”
In Jules Verne’s 1864 science fiction classic, “Journey to the Center of the Earth”, a German professor, his nephew, and their guide descend into the planet through an Icelandic volcano—encountering caverns, an underground ocean, living dinosaurs, strange sea creatures, and even a prehistoric giant herding mastodons along the way—and are ultimately expelled through the a volcano on the coast of Sicily.
In the real world, no human could survive the unimaginable heat and crushing pressure, even if there were a vehicle capable of digging to the core, Vidale said.
It’s true that the outer core generates electrical currents that support the planet’s magnetic field, but Vidale says changes in the Texas-sized inner core are too tiny to have an impact.
“The mechanics is that the outer core rotates and creates a magnetic field, and so it somehow pulls the inner core back and forth.”Vidale also said.
Heated debate among researchers
The latest discoveries about the inner core have fueled vigorous disagreements among leading Earth scientists and given rise to opposing theories, Vidale says. Some don’t think the core rotates at all. Some insist that surface forces, such as earthquakes, temporarily alter the rotation.
“It’s interesting because the nucleus is quite large, it moves with measurable amounts, and it’s a mystery. We are making progress and seeing more things, talking to people all over the world and trying to get more data (…) What our work has done is that it has convinced the majority of the community”the scientist concluded.
