Scientists now know that the Earth has two magnetic poles (North pole and South pole) tilted at nearly 22 degrees. These poles are essential as magnetic field lines run between them from north to south outside the Earth and south to north inside the Earth which prevents our planet from harmful cosmic rays.
In a new study, researchers have claimed that Earth was not dipolar in the past and it had more than two magnetic poles, in fact, it had several pairs of magnetic poles.
Earth’s magnetism is due to its core which is made of molten iron. Earth’s core was not solid from the start but it was once molten and later it started to solidify. Researchers from the Carnegie Institution of Science believe that Ancient Earth had multiple poles for some time during the transition.
Scientists wanted to test the magnetic properties of Earth when it had molten core. For the study, researchers examined rocks that had magnetic properties since their formation. Scientists know that Earth was dipolar for nearly 4 billion years, but something happened to its dipolar nature between 0.5 and 1 billion years ago (also known as Neoproterozoic Era).
In the study, it was found that Earth’s core was changing from molten to solid state that created havoc to magnetic field nearly a billion years ago and our planet got several pairs of magnetic poles. However, things started to settle down as the transition phase of core got over and Earth again became dipolar in nature.
“These findings could offer an explanation for the bizarre fluctuations in magnetic field direction seen in the geologic record around 600 to 700 million years ago,” Driscoll added. “And there are widespread implications for such dramatic field changes.”
The study appeared in the Geographical research letters.