A new model reveals how the Earth's core maintained a stable magnetic field even before the inner core formed, providing insights into the origins of life and our technological future.
Earth benefits from the presence of a magnetic field, which acts as a shield against harmful cosmic radiation and makes life possible. In contrast, planets like Mars are exposed to a constant shower of charged particles that create a much more hostile environment.
Scientists attribute Earth’s magnetic field to what is known as the dynamo theory. According to this explanation, the slow cooling of the liquid iron-nickel core causes strong convection currents in the outer core. As the Earth rotates, these currents are deflected, moving in spiral-like patterns. The movement of the liquid metal creates electric currents, and these create magnetic fields, which account for much of Earth’s protective magnetic field.
But this theory has a limitation. Before the inner core began to solidify—an event that occurred about a billion years ago—it was entirely liquid. This raises a critical question: Could a magnetic field have existed at this early time?
A recent study published in Nature offers an answer. Three Chinese geophysicists present new insights that shed light on this long-standing mystery.
A new model provides the answer
Since it is impossible to directly observe the Earth's interior and the processes that occur within it, Earth scientists study them using computer models.
The scientists developed a model of the Earth to test in simulations whether a completely liquid core could also create a stable magnetic field. Their simulations were partly calculated on the high-performance computer Piz Daint at CSCS in Lugano.
In the simulations, the researchers show the correct physical regime in which the viscosity of the Earth's core has no influence on the dynamo effect. This means that the Earth's magnetic field was formed in its early history in a similar way to today.
The team of researchers are the first to successfully minimize the effect of the Earth's core viscosity to a negligible value in the model. "Until now, no one has been able to perform such calculations under these correct physical conditions," says the study's lead author, Yufeng Li.
Understanding the history of the Earth's magnetic field
"This finding helps us better understand the history of the Earth's magnetic field and is useful in interpreting data from the geological past," says co-author Andy Jackson.
The finding also sheds a new light on the emergence of life. Billions of years ago, life probably benefited from the magnetic field, which blocked harmful radiation from space, making its development possible in the first place.
Researchers can also use the new findings to study the magnetic fields of other celestial bodies, such as the Sun or the planets Jupiter and Saturn.
But Earth's magnetic field doesn't just protect life. It plays a vital role in enabling satellite communications and many other aspects of modern civilization. "It's therefore important to understand how the magnetic field is formed, how it changes over time, and what mechanisms maintain it," says Jackson. "If we understand how the magnetic field is formed, we can predict its future evolution."
DOI: 10.1038/s41586-025-09334-y
More of the topic in Hayadan:
2 תגובות
What on earth did you bring God into the room for? We are still trying to understand the ramifications of this article and its ramifications and you have already brought up the name of God? Are you what is called a "lazy-brain"??
There is a proverb that says the heavens are God's and the earth is for humans, and the other says not to explore the depths of the sea. And yet, research is sometimes good for humans and sometimes unnecessary. In this case, when the Creator decides to make a small hole in the atmosphere to destroy half or all of humanity, of course, it depends on many variables, so no one can stop it.