[{"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\/da\/article\/modal\/6973\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 magnetic poles could start to flip. What happens then?\u003C\/h2\u003E\u003Cp\u003EThis is a possibility that we may start to face not in the next million years, not in the next thousand, but in the next hundred. If Earth\u2019s magnetic field were to decay significantly, it could collapse altogether and flip polarity \u2013 changing magnetic north to south and vice versa. The consequences of this process could be dire for our planet.\u003C\/p\u003E\u003Cp\u003EMost worryingly, we may be headed right for this scenario.\u003C\/p\u003E\u003Cp\u003E\u2018The geomagnetic field has been decaying for the last 3,000 years,\u2019 said Dr Nicolas Thouveny from the European Centre for Research and Teaching of Environmental Geosciences (CEREGE) in Aix-en-Provence, France. \u2018If it continues to fall down at this rate, in less than one millennium we will be in a critical (period).\u2019\u003C\/p\u003E\u003Cp\u003EDr Thouveny is one of the principal investigators on the five-year \u003Ca href=\u0022https:\/\/cordis.europa.eu\/result\/rcn\/195450_en.html\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003EEDIFICE\u003C\/a\u003E project, which has been running since 2014. Together with his colleagues, he has been investigating the history of Earth\u2019s magnetic field, including when it has reversed in the past, and when it might again.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECosmic rays\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EOur planet\u2019s magnetic field is predominantly created by the flow of liquid iron inside the core. It has always been a feature of our planet, but it has flipped in polarity repeatedly throughout Earth\u2019s history. Each time it flips \u2013 up to 100 times in the past 20 million years, while the reversal can take about 1,000 years to complete \u2013 it leaves \u003Ca href=\u0022https:\/\/theconversation.com\/the-earths-magnetic-field-reverses-more-often-now-we-know-why-96957\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Efossilised magnetisation\u003C\/a\u003E in rocks on Earth.\u003C\/p\u003E\u003Cp\u003EBy taking cores - or columns - of sediments from the sea floor, like a long straw that can extend down up to 300 metres with the help of a drill, we can look back in time and see when these reversals occurred. Dr Thouveny and his team looked at two particular forms of elements that allowed them to probe the history of our planet\u2019s magnetic field in greater detail.\u003C\/p\u003E\u003Cp\u003EFor a polarity reversal to occur, the magnetic field needs to weaken by about 90% to a threshold level. This process can take thousands of years, and during this time, the lack of a protective magnetic shield around our planet allows more cosmic rays \u2013 high-energy particles from elsewhere in the universe \u2013 to hit us.\u003C\/p\u003E\u003Cp\u003EWhen this happens, these cosmic rays collide with more and more atoms in our atmosphere, such as nitrogen and oxygen. This produces variants of elements called cosmogenic isotopes, such as carbon-14 and beryllium-10, which fall to the surface. And by studying the quantities of these in cores, we can see when polarity reversals took place.\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022text-center text-blue font-bold text-2xl w-full lg:w-1\/2 border-2 border-blue p-12 my-8 lg:m-12 lg:-ml-16 float-left\u0022\u003E\n  \u003Cspan class=\u0022text-5xl rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n  \u003Cp class=\u0022font-serif italic\u0022\u003E\u2018The geomagnetic field has been decaying for the last 3,000 years.\u2019\u003C\/p\u003E\n  \u003Cfooter\u003E\n    \u003Ccite class=\u0022not-italic font-normal text-sm text-black\u0022\u003EDr Nicolas Thouveny, CEREGE\u003C\/cite\u003E\n  \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003EThe last reversal occurred between 772,000 and 774,000 years ago. Since then, the field has almost reversed 15 times, called an excursion, dropping in strength significantly but not quite reaching the threshold needed before rising again. This is when we are most at risk - as the field decays and then recovers its strength. The last excursion occurred 40,000 years ago, and evidence suggests we are heading in that direction again.\u003C\/p\u003E\u003Cp\u003E\u2018The geomagnetic field has been losing 30 percent of its intensity in the last 3,000 years,\u2019 said Dr Thouveny. \u2018From this value, we predict it will drop to near zero in a few centuries or a millennia.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ESatellites\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EToday, we can already see the effects of a weakened magnetic field on our satellites in orbit.\u003C\/p\u003E\u003Cp\u003EIn the Atlantic Ocean between South America and Africa, there is a vast region of Earth\u2019s magnetic field that is about three times weaker than the field strength at the poles.\u003C\/p\u003E\u003Cp\u003EThis is called the \u003Ca href=\u0022https:\/\/m.esa.int\/Our_Activities\/Observing_the_Earth\/Swarm\/Earth_s_magnetic_heartbeat\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003ESouth Atlantic Anomaly\u003C\/a\u003E (SAA), and it\u2019s the focus of the \u003Ca href=\u0022https:\/\/cordis.europa.eu\/project\/rcn\/213916_en.html\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003ECoreSat\u003C\/a\u003E project being led by Professor Chris Finlay from the Technical University of Denmark (DTU) near Copenhagen. Using data from multiple satellites, including the European Space Agency\u2019s (ESA) three Swarm satellites launched in 2013, this project is trying to figure out what is causing the SAA.\u003C\/p\u003E\u003Cp\u003E\u2018This is a region where we see that satellites consistently (experience) electronic failures,\u2019 said Prof. Finlay. \u2018And we don\u2019t understand where this weak field region is coming from, what\u2019s producing it, and how it might change in the future.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@alignleft@\u0022\u003E\n\u003Cimg alt=\u0022The Earth\u0027s magnetic field has been weakening over the South Atlantic (blue region). Image credit - ESA\/DTU Space\u0022 height=\u00221840\u0022 src=\u0022\/research-and-innovation\/sites\/default\/files\/hm\/IMCEUpload\/June_2014_magnetic_field.jpg\u0022 title=\u0022The Earth\u0027s magnetic field has been weakening over the South Atlantic (blue region). Image credit - ESA\/DTU Space\u0022 width=\u00222300\u0022\u003E\n\u003Cfigcaption class=\u0022italic mb-4\u0022\u003EThe Earth\u0027s magnetic field has been weakening over the South Atlantic (blue region). Image credit - ESA\/DTU Space\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003EScientists first noticed the SAA in the 1950s, and since then it has decreased in strength by a further 6%, as well as moving closer to the west. \u2018(There) hasn\u2019t really been any convincing explanation of it,\u2019 said Prof. Finlay, adding that scientists haven\u2019t been able to predict how it\u2019s going to alter.\u003C\/p\u003E\u003Cp\u003EThe CoreSat project is hoping to change all that, using the most detailed data available yet to study the properties of the magnetic field here and how it shifts over time. By probing the SAA, the team are hoping to see what\u2019s going on inside Earth\u2019s core that might be causing it.\u003C\/p\u003E\u003Cp\u003EOne possibility is that there could be a vast anticyclone in the southern portion of Earth\u2019s liquid metal outer core, which may be pushing out the magnetic field from the South Atlantic region. Another possibility is that the magnetic field in this region is pointing the wrong way \u2013 in effect, there\u2019s a mini-polarity reversal taking place.\u003C\/p\u003E\u003Cp\u003EThe SAA gives us a direct look at how a weakened magnetic field can affect satellites, as numerous spacecraft have reported electronic malfunctions when flying over this region as they are hit by cosmic rays. But it\u2019s unclear at the moment if the SAA has any relation to the Earth\u2019s magnetic field flipping in polarity, which is also something Prof. Finlay and his team will investigate.\u003C\/p\u003E\u003Cp\u003E\u2018In some simulations you see features like the SAA growing during a pole reversal,\u2019 he said. \u2018It\u2019s not necessarily the case, but it wouldn\u2019t be a surprise if something like this was involved in a magnetic reversal.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EA glimpse\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003ENevertheless, the SAA just might give us a glimpse of what is to come in the near future. If \u003Ca href=\u0022https:\/\/news.nationalgeographic.com\/news\/2004\/09\/earths-magnetic-field-is-fading\/\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Etrends continue\u003C\/a\u003E, our planet\u0027s magnetic field could reverse again in one or two millennia. Prior to that, the field may continue to weaken, and within a century we could be faced with serious problems.\u003C\/p\u003E\u003Cp\u003E\u2018The decrease in geomagnetic field is much more important and dramatic than the reversal,\u2019 said Dr Thouveny. \u2018It is very important to understand if the present field will decay to zero in the next century, because we will have to prepare.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThe research in this article was funded by the European Research Council. 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