A major dip in the Earth\u2019s magnetic field over the South Atlantic has been puzzling scientists for over a century.<\/p>\n
Perhaps most strangely, the weak spot \u2014 dubbed the South Atlantic Anomaly<\/a> \u2014 has grown rapidly over the last eleven years. That\u2019s according to satellite data suggests showing it\u2019s expanded by an area equivalent to half the size of continental Europe, as detailed in a new paper<\/a> published in the journal Physics of the Earth and Planetary Interiors.<\/p>\n An international team of researchers analyzed data collected by the European Space Agency\u2019s Swarm, a constellation comprised of three identical satellites that measure the Earth\u2019s magnetic signals.<\/p>\n The findings could allow us to improve existing magnetic models that play a crucial role in navigation and tracking of space weather, while also furthering our understanding of how the Earth\u2019s layers interact with each other.<\/p>\n Scientists\u2019 best theory is that an enormous, swirling body of molten iron in the planet\u2019s outer core \u2014 roughly 1,800 miles below the surface \u2014 could be generating the major dip in the magnetic field.<\/p>\n But that\u2019s only one of many factors influencing this weakening, with scientists working to identify the other factors at play. As detailed in this latest paper, the spot is behaving in all kinds of unexpected ways as it continues to expand rapidly.<\/p>\n \u201cThe South Atlantic Anomaly is not just a single block,\u201d said lead author and Technical University of Denmark professor of geomagnetism Chris Finlay in a statement<\/a>. \u201cIt\u2019s changing differently towards Africa than it is near South America. There\u2019s something special happening in this region that is causing the field to weaken in a more intense way.\u201d<\/p>\n \u201cNormally we\u2019d expect to see magnetic field lines coming out of the core in the southern hemisphere,\u201d Finlay explained. \u201cBut beneath the South Atlantic Anomaly we see unexpected areas where the magnetic field, instead of coming out of the core, goes back into the core.\u201d<\/p>\n Besides the anomaly, Swarm data has also found that the magnetic field is strengthening over Siberia, while weakening over Canada.<\/p>\n Scientists believe the complex processes behind the shifts are linked to the northern magnetic pole wandering towards Siberia over the last few years.<\/p>\n \u201cWhen you\u2019re trying to understand Earth\u2019s magnetic field, it\u2019s important to remember that it\u2019s not just a simple dipole, like a bar magnet,\u201d said Finlay. \u201cIt\u2019s only by having satellites like Swarm that we can fully map this structure and see it changing.\u201d<\/p>\n The ESA is expected to extend its Swarm mission beyond 2030, which could allow researchers to continue tracking the odd behavior of our planet\u2019s magnetic field for many years to come.<\/p>\n