The chaotic magnetic field of the ancient Earth

Earth used to have more than two magnetic poles in the past, and the magnetosphere's ability to protect against harmful radiation from the Sun was much weaker than it is today.

Illustration of Earth's ancient and present magnetic field. Photo: Peter Driscoll.

According to Mother Nature Network, Earth today has two magnetic poles, one in the north and one in the south, but this arrangement was not true in the past.

In a study by the Carnegie Institution for Science, USA, published in the journal Geophysical Research Letters on June 6, the Earth's magnetosphere was completely different from the present between 500 million and one billion years ago. Many magnetic poles suddenly appeared around the world, causing chaos in the magnetic field, affecting living things.

"This discovery could provide an explanation for the strange fluctuations in magnetic field direction found in the geological record around 600-700 million years ago," said study co-author Peter Driscoll.

The magnetosphere protects Earth, deflecting harmful high-energy particles from the Sun and space. Photo: NASA.

According to scientists, the Earth's magnetic field is created by the planet's liquid iron core rotating around a smaller solid core, but the inner core has not always been solid. At some point in Earth's history, the inner core must have undergone a transition from a molten state to a solid.

Driscoll believes this event occurred between 500 million and a billion years ago, when the inner core began to solidify, wreaking havoc on Earth's magnetic field. This chaotic period lasted until the inner core solidified completely.

The research results significantly change the understanding of the Earth's geological history, especially magnetic measurements used to reconstruct the movements of ancient continents and climate zones. The magnetosphere is responsible for shielding harmful radiation from the Sun. In the past, the magnetic field, which included many magnetic poles, had much weaker protective power than it does today.

According to VNE