The Earth's inner core may have changed shape in the past 20 years, according to a group of scientists.
Our planet's inner core is commonly believed to be ball-shaped, but its edges may have been deformed by 100 meters or more upwards in some places, according to Professor John Vidale, who led the research.
The Earth's core is the beating heart of our planet because it produces a magnetic field that prevents life from being scorched by the Sun's radiation.
The inner core rotates independently of the liquid outer crust and the rest of our planet.
Without this movement, Earth would die and become more like barren Mars, which lost its magnetic field billions of years ago.
The shape change could occur at the points where the edge of the solid inner core meets the extremely hot liquid metallic outer core.
The research was published in a scientific journal Nature Geoscience.
Scientists initially tried to figure out why the inner core slowed down relative to the Earth's rotation speed before speeding up again in 2010.
Understanding how the Earth's core works is key to understanding the magnetic field that protects our planet and whether it could weaken or break.
- The Northern Lights enchanted us in 2024, will they continue to do so in the future?
- What happens around the world during a full moon
- Historic moment: NASA spacecraft almost touches the Sun
The interior of our planet is an extremely mysterious place.
The core is located about 6.400 kilometers from the Earth's surface and, despite their best efforts, scientists have so far been unable to reach it.
And so, in an attempt to unravel its secrets, some scientists have begun measuring the shock waves caused by earthquakes as they rip through the planet.
The way the waves travel reveals what type of material they pass through, including the inner core, and helps to build a picture of what lies beneath our feet.
The new analysis looked at seismic wave patterns originating from earthquakes that recurred in the same locations between 1991 and 2023.
This helped to show how the inner core changed over time.
Professor Vidale, a scientist at the University of Southern California, has found more evidence to support the theory that during those years the inner core slowed down sometime around 2010.
But his team also found evidence for a changing shape of the inner core.
This appears to occur at the boundary between the inner and outer cores, where the inner core is close to its melting point.
The deformation could be caused by the fluid flow of the outer core, as well as the strength of the unequal gravitational force.
Professor Hrvoje Tkalčić from the Australian National University, who was not involved in the study, said the study presents "an interesting concept that deserves further investigation."
He says it could allow scientists to "make estimates with greater confidence about some material properties, such as the viscosity of the inner core, which is one of the least known quantities in modern science."
Over time, the liquid outer core freezes into a solid inner core, but it will be billions of years before it completely solidifies.
This will almost certainly mean the end of life on Earth, but by then the planet will most likely have already been swallowed by the Sun anyway.
Professor Vidale's work is part of a growing body of research by experts around the world who are studying and debating what exactly happens in the core.
"In science, we usually try to observe things until we understand them," says Professor Vidale.
"There's every chance this discovery won't have any impact on our daily lives, but we really want to understand what's going on at the center of the Earth," he adds.
It is possible that the changes are related to changes in the Earth's magnetic field.
"The magnetic field has had jerks at various times over the past few decades, and we'd like to know if those are related to what we're seeing at the inner core boundary," he said.
Professor Vidale urged caution about exaggerating these findings into ideas that the core will stop rotating anytime soon.
He also added that there are still many unknowns.
"We're not 100 percent sure we're interpreting these changes correctly," he said, adding that the frontiers of scientific knowledge are constantly changing and that, like many other researchers, if not all, he has made mistakes in the past.
Follow us on Facebook, Twitter, Instagram, YouTube i Viber.
If you have a topic suggestion for us, please contact bbcnasrpskom@bbc.co.uk
- Another celestial body fell with the asteroid that wiped out the dinosaurs
- What is an eclipse and how many different types are there?
- Astronomers uncover 'murder mystery', a cosmic secret kept for 37 years
Bonus video:
