The Earth's iron core isn't just a solid mass

According to a new "holy grail" scientific discovery, the blazing-hot ball of metal at the center of the Earth's core is actually more active than one might think. In fact, it might be host to a centra-planet molecular dinner party.

Using machine learning and a supercomputer, physicists at the University of Texas at Austin and Sichuan and Nanjing Universities in China have reported the possibility of moving iron atoms at the center of the Earth, which might explain some of the dense inner core's "soft" physical properties.

For context: the Earth's center is a solid metal inner core surrounded by a liquid metal outer core. It's about 750 miles thick and reaches 9,800 degrees Fahrenheit (or about 5,400 degrees Celsius). The movement of atoms in the liquid outer core generate the Earth's magnetic field and the planet's broad habitability. But while the center of our planet has long been thought to be a solid iron center, recent research theorized that a portion of the dense inner core might actually be liquid, as well.

The new study postulates that the core's iron atoms migrate into new positions "like people changing seats at a dinner table," without disturbing the underlying metallic structure of the iron and making the core more malleable. The concept is known as "collective motion."

“Seismologists have found that the center of the Earth, called the inner core, is surprisingly soft, kind of like how butter is soft in your kitchen,” explained Youjun Zhang, a Sichuan University professor. “The big discovery that we’ve found is that solid iron becomes surprisingly soft deep inside the Earth because its atoms can move much more than we ever imagined. This increased movement makes the inner core less rigid, weaker against shear forces.”

Zhang and his fellow researchers used a miniature computer model of the Earth's inner core to predict the properties and motion of the core's iron atoms. Fed by data collected from high pressure-temperature lab experiments designed to emulate conditions of Earth's inner core, the findings were then compared to seismic-wave studies of the Earth's inner core and laboratory shock-wave experiments that tested the expected collective motion of iron atoms at extreme pressure and temperature.

"The discovery implies that the same physics in collective motion also occurs in other planetary interiors such as Mars and exoplanetary interiors," said Jung-Fu Lin, a professor at the University of Texas Jackson School of Geosciences, in an interview with Newsweek.

Science's obsession with the unreachable inner core — which is still holding onto heat from the Earth's formation 4.5 billion years ago — has led to predictive models and research suggesting various explanations of movement, composition, and shape. As well as a plethora of misleading information.

But, even with science getting closer to explaining the intricacies of our planet and its dancing atoms, the Earth's evolving layers have yet to be pulled back fully.