[{"command":"openDialog","selector":"#drupal-modal","settings":null,"data":"\u003Cdiv id=\u0022republish_modal_form\u0022\u003E\u003Cform class=\u0022modal-form-example-modal-form ecl-form\u0022 data-drupal-selector=\u0022modal-form-example-modal-form\u0022 action=\u0022\/en\/article\/modal\/10710\u0022 method=\u0022post\u0022 id=\u0022modal-form-example-modal-form\u0022 accept-charset=\u0022UTF-8\u0022\u003E\u003Cp\u003EHorizon articles can be republished for free under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.\u003C\/p\u003E\n \u003Cp\u003EYou must give appropriate credit. We ask you to do this by:\u003Cbr \/\u003E\n 1) Using the original journalist\u0027s byline\u003Cbr \/\u003E\n 2) Linking back to our original story\u003Cbr \/\u003E\n 3) Using the following text in the footer: This article was originally published in \u003Ca href=\u0027#\u0027\u003EHorizon, the EU Research and Innovation magazine\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003ESee our full republication guidelines \u003Ca href=\u0027\/horizon-magazine\/republish-our-stories\u0027\u003Ehere\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003EHTML for this article, including the attribution and page view counter, is below:\u003C\/p\u003E\u003Cdiv class=\u0022js-form-item form-item js-form-type-textarea form-item-body-content js-form-item-body-content ecl-form-group ecl-form-group--text-area form-no-label ecl-u-mv-m\u0022\u003E\n \n\u003Cdiv\u003E\n \u003Ctextarea data-drupal-selector=\u0022edit-body-content\u0022 aria-describedby=\u0022edit-body-content--description\u0022 id=\u0022edit-body-content\u0022 name=\u0022body_content\u0022 rows=\u00225\u0022 cols=\u002260\u0022 class=\u0022form-textarea ecl-text-area\u0022\u003E\u003Ch2\u003EEarth\u2019s core, replete with oceans and cyclones, is being demystified \u003C\/h2\u003E\u003Cp\u003EAt the centre of Earth is a vast ball of metal, the planet\u2019s core. While unreachable without the help of Jules Verne, it can be studied and plays a vital role for the world.\u003C\/p\u003E\u003Cp\u003EThe iron-nickel interior generates a magnetic field that protects the planet from harmful radiation and allows life to flourish. Exactly how this magnetic field is created, and whether it is the same on other worlds, are open questions.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EIron oceans\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003ENew research is revealing more about planetary cores and magnetic fields than ever before \u2013 and hinting at changes that take place 3\u0026nbsp;000 kilometres under people\u2019s feet.\u003C\/p\u003E\u003Cp\u003EEarth has a solid inner core about 1 200 km across, surrounded by a liquid iron outer core that extends another 2\u0026nbsp;200 km. In the outer core, as the liquid metal circulates it generates a magnetic field.\u003C\/p\u003E\u003Cp\u003E\u2018We\u2019re trying to understand the dynamics of the big iron oceans that are present in planets like Earth,\u2019 said Michael Le Bars of the French National Centre for Scientific Research, or CNRS. \u2018The flow in there is responsible for the magnetic field of the planets. And this magnetic field is one of the key ingredients for life.\u2019\u003C\/p\u003E\u003Cp\u003ELe Bars studied these matters as part of a European project that received EU funding to spur advances in the field including through laboratory experiments. Called \u003Ca href=\u0022https:\/\/cordis.europa.eu\/project\/id\/681835\u0022\u003EFLUDYCO\u003C\/a\u003E, the initiative ran from mid-2016 until end-2021.\u003C\/p\u003E\u003Cp\u003EIn labs, Le Bars and his team injected dye into a water-filled rubber ball and then rotated it to deform the sphere, simulating tidal distortions in Earth\u2019s core.\u003C\/p\u003E\u003Cp\u003EThey also popped a balloon containing a liquid metal called Galinstan inside water to simulate the formation of a planetary core. Finally, the researchers tracked the interaction of lower and higher density water to study the convection and turbulence of an outer core.\u003C\/p\u003E\u003Cp\u003EThe team found that there were three ways to drive circulation inside a liquid iron core.\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022\u003E\n\u003Cimg alt=\u0022Researchers from the FLUDYCO project used lab models to simulate the flows in planetary cores. \u00a9 T. Le Reun \u0026amp; M. Le Bars (IRPHE) and G. Hennenfent (Le Chromophore)\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022695d8899-6a3d-4a77-af06-6973b497ef9b\u0022 src=\u0022\/sites\/default\/files\/hm\/IMCEUpload\/Picture2.png\u0022\u003E\n\u003Cfigcaption class=\u0022tw-italic tw-mb-4\u0022\u003EResearchers from the FLUDYCO project used lab models to simulate the flows in planetary cores. \u00a9 T. Le Reun \u0026amp; M. Le Bars (IRPHE) and G. Hennenfent (Le Chromophore)\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWorldly ways\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EThe first was by metallic iron swirling in the outer core. This process, called convection, results from the cooling and solidifying of the planet\u2019s core.\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022tw-text-center tw-text-blue tw-font-bold tw-text-2xl lg:tw-w-1\/2 tw-border-2 tw-border-blue tw-p-12 tw-my-8 lg:tw-m-12 lg:tw--ml-16 tw-float-left\u0022\u003E\n \u003Cspan class=\u0022tw-text-5xl tw-rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n \u003Cp class=\u0022tw-font-serif tw-italic\u0022\u003EThis magnetic field is one of the key ingredients for life.\r\n\r\n\u003C\/p\u003E\n \u003Cfooter\u003E\n \u003Ccite class=\u0022tw-not-italic tw-font-normal tw-text-sm tw-text-black\u0022\u003EMichael Le Bars, FLUDYCO\u003C\/cite\u003E\n \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003EAnother method was tidal forces caused by the gravitational push and pull of a nearby object \u2013 perhaps like the magnetic moon \u003Ca href=\u0022https:\/\/www.esa.int\/Science_Exploration\/Space_Science\/Juice\/Spotlight_on_Ganymede_Juice_s_primary_target\u0022\u003EGanymede\u003C\/a\u003E, which orbits Jupiter and is \u003Ca href=\u0022https:\/\/en.wikipedia.org\/wiki\/Ganymede_(mythology)\u0022\u003Enamed\u003C\/a\u003E after a Trojan prince in Greek mythology.\u003C\/p\u003E\u003Cp\u003EThe third involved crystals of solidified iron forming in the liquid outer core and driving the circulation, a reverse of the solidification happening in Earth\u2019s core.\u003C\/p\u003E\u003Cp\u003E\u2018It\u2019s snowing iron ice crystals towards the inside and mixing the fluid,\u2019 Le Bars, Marseille-based director of research at CNRS, said of the third method. \u2018It\u2019s a very strange process.\u2019\u003C\/p\u003E\u003Cp\u003EWhat remains unclear is exactly which worlds would have which method to produce their metallic fields or whether other processes might be involved for gas giants like Jupiter.\u003C\/p\u003E\u003Cp\u003E\u2018Each planet seems to be different,\u2019 said Le Bars. \u2018We don\u2019t know if Ganymede\u2019s core is convecting or snowing.\u2019\u003C\/p\u003E\u003Cp\u003EA European spacecraft launched in April 2023 and due to reach Jupiter in 2031 will orbit Ganymede and could produce revelations about its core, perhaps helping to ascertain how worlds like this generate a magnetic field.\u003C\/p\u003E\u003Cp\u003EIn Earth\u2019s solar system, Saturn, Uranus and Neptune also have substantial magnetic fields.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EOrbit observation\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EAnother way to investigate planetary cores is to make indirect measurements of them.\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022tw-text-center tw-text-blue tw-font-bold tw-text-2xl lg:tw-w-1\/2 tw-border-2 tw-border-blue tw-p-12 tw-my-8 lg:tw-m-12 lg:tw--ml-16 tw-float-left\u0022\u003E\n \u003Cspan class=\u0022tw-text-5xl tw-rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n \u003Cp class=\u0022tw-font-serif tw-italic\u0022\u003EIn the same way you get cyclones and hurricanes in the atmosphere, we also have that happening in Earth\u2019s core.\r\n\r\n\u003C\/p\u003E\n \u003Cfooter\u003E\n \u003Ccite class=\u0022tw-not-italic tw-font-normal tw-text-sm tw-text-black\u0022\u003EChris Finlay, CoreSat\u003C\/cite\u003E\n \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003EAn EU-funded project called \u003Ca href=\u0022https:\/\/cordis.europa.eu\/project\/id\/772561\u0022\u003ECoreSat\u003C\/a\u003E has been doing this from orbit by using three European Space Agency satellites that study changes in Earth\u2019s magnetic field.\u003C\/p\u003E\u003Cp\u003EThe initiative, due to wrap up in August 2023 after five and a half years, is led by Chris Finlay of the National Space Institute at the Technical University of Denmark near Copenhagen.\u003C\/p\u003E\u003Cp\u003EEarth\u2019s magnetic field can strengthen and weaken, altering its structure including the locations of the magnetic poles by tens of kilometres a year, or sometimes even \u003Ca href=\u0022https:\/\/projects.research-and-innovation.ec.europa.eu\/en\/horizon-magazine\/earths-magnetic-poles-could-start-flip-what-happens-then\u0022\u003Eflip in polarity entirely\u003C\/a\u003E \u2013 something thought to happen every few 100\u0026nbsp;000 years or so.\u003C\/p\u003E\u003Cp\u003EFinlay says the satellites are showing how the magnetic field is changing.\u003C\/p\u003E\u003Cp\u003EUsing data from the satellites, Finlay and his colleagues have been seeking a clearer picture of the magnetic field at the boundary between Earth\u2019s lower mantle and the outer core.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMagnetic signal\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EA major difficulty has been picking out the magnetic field signal from the core among the other magnetic fields produced at and above Earth\u2019s surface.\u003C\/p\u003E\u003Cp\u003EOne technique has been to monitor Earth\u2019s upper atmosphere and its aurora at the poles and identify a cleaner signature of changes in the core\u2019s magnetic field.\u003C\/p\u003E\u003Cp\u003EThe goal is to have systems that can predict how the magnetic field is going to change over the coming decades, according to Finlay.\u003C\/p\u003E\u003Cp\u003E\u2018It\u2019s been challenging,\u2019 he said. \u2018We\u2019d like to do something like in weather forecasting, where they have models of the general circulation of the atmosphere and make forecasts.\u2019\u003C\/p\u003E\u003Cp\u003EStudying changes in the core\u2019s magnetic field is important for understanding the habitability of Earth and other worlds.\u003C\/p\u003E\u003Cp\u003ENowhere are these changes more noticeable than in the South Atlantic region.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EUnderground hurricanes\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EOff the coast of South America, Earth\u2019s magnetic field weakens more than 50%.\u003C\/p\u003E\u003Cp\u003EWhile the cause of this phenomenon known as the South Atlantic Anomaly is unknown, projects like CoreSat are providing additional information.\u003C\/p\u003E\u003Cp\u003E\u2018We\u2019ve been able to see more details,\u2019 Finlay said. \u2018We\u2019re still working on it.\u2019\u003C\/p\u003E\u003Cp\u003EIt appears that, down at the boundary of the core and mantle underneath the anomaly, the magnetic field is reversed.\u003C\/p\u003E\u003Cp\u003EThat could be a sign of weather-like systems in the outer core caused by temperature differences and the rotation of the planet.\u003C\/p\u003E\u003Cp\u003E\u2018In the same way you get cyclones and hurricanes in the atmosphere, we also have that happening in Earth\u2019s core,\u2019 said Finlay. \u2018This organises the convections into large circulations in the outer core.\u2019\u003C\/p\u003E\u003Cp\u003EThat said, the swirling inside Earth occurs at much slower speeds \u2013 20 km a year compared with wind velocities of up to 250 km an hour in hurricanes.\u003C\/p\u003E\u003Cp\u003EEven with the advances in research, there is much still to learn about planetary interiors and the implications are broad.\u003C\/p\u003E\u003Cp\u003E\u2018Today we are looking at other planets to find life on them,\u2019 said Le Bars of CNRS. \u2018To have life, you need a magnetic field to protect the planet.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EResearch in this article was funded by the EU via the European Research Council (ERC). 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