Geophysicists from the University of Leeds claim to have discovered how anomalies arise in the Earth’s magnetic field, thanks to research recently published in the scientific journal Nature Geoscience. As the scientists involved in the study have revealed, the reason for these peculiarities in the Earth’s magnetic field are due to the irregular distribution of heat within the earth’s core.
Both the internal heat and the magnetic field of our planet are born in its core, an enormous mass of molten iron, up to 5,000 degrees, which rotates at high speed creating the effect of a dynamo. A movement that is maintained thanks to the convective currents that cause heat to flow from the core to the mantle. However, a new study has shown that this process does not occur uniformly throughout the volume of our planet and this is what causes magnetic anomalies.
How do magnetic anomalies occur?
Seismic analysis has shown that there is mantle regionsfor example, under Africa and the Pacific Ocean, especially hot. Computer simulations conducted by the researchers show that core cooling is slower in these zones due to a small temperature difference. Due, convective flows are much weaker and so is the magnetic fieldwhich is projected into space over the South Atlantic, causing problems to satellites in orbit and communication.
“One of the things that the magnetic field in space does is deflect charged particles emitted by the Sun. When the magnetic field is weaker, this protective shield is not as effective,” explains Dr Jonathan Mound of the School of Earth and Environment and author of the study, to which he adds: “So when satellites pass over that area, these charged particles can disrupt and interfere with their operations.”
Finally, previously, scientists could only guess at the causes of this anomaly, so it was unknown how long they could exist. However, it is now clear to scientists that the change in flows at the core-magma boundary can last tens of millions of years, so it can be argued that they will persist for a long time. “Processes in the mantle occur very slowly, so we can expect temperature anomalies in the lower mantle to have stayed the same for tens of millions of years,” Mound reveals, adding: “Therefore, we would expect that the properties of the magnetic field they create have also been similar for tens of millions of years.”