[{"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\/7384\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\u003ECould there be life on Jupiter\u2019s moons?\u003C\/h2\u003E\u003Cp\u003EThree of Jupiter\u2019s four largest moons are icy, and in 1998 NASA\u2019s Galileo spacecraft detected \u003Ca href=\u0022https:\/\/www.nasa.gov\/feature\/goddard\/2019\/nasa-scientists-confirm-water-vapor-on-europa\/\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Etantalising hints\u003C\/a\u003E of an ocean beneath one, Europa. Since then, further studies have detected \u003Ca href=\u0022https:\/\/www.theguardian.com\/science\/2016\/sep\/26\/jupiter-europa-water-plumes-nasa\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Esigns of water plumes\u003C\/a\u003E possibly erupting from this ocean.\u003C\/p\u003E\u003Cp\u003EThe other two large icy moons, Ganymede and Callisto, are also thought to have oceans beneath their surfaces. Now, new questions are being asked: if there is water on these moons, could there be life? And could we look for it?\u003C\/p\u003E\u003Cp\u003ETo help answer that question, the European Space Agency is planning to send a spacecraft to Jupiter in 2022, called the \u003Ca href=\u0022https:\/\/sci.esa.int\/web\/juice\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003EJupiter Icy Moons Explorer\u003C\/a\u003E (JUICE). Scheduled for arrival by 2029, it will perform multiple flybys of Europa and Callisto before entering orbit around Ganymede from 2032-2034 \u2013 the first spacecraft to orbit a moon other than Earth\u2019s moon. During this time, it will return invaluable data back to Earth.\u003C\/p\u003E\u003Cp\u003EBefore it even gets there, however, scientists are already busy studying these moons for signs of habitability, and preparing for the data that will be returned by the mission.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ETrapped\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EThe \u003Ca href=\u0022https:\/\/europa.nasa.gov\/europa\/ocean\/\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Eoceans under these moons\u003C\/a\u003E are likely large, spanning the entire moons\u2019 circumferences and extending tens of kilometres deep. But they are also trapped under tens of kilometres of ice, making studies of them very difficult.\u003C\/p\u003E\u003Cp\u003EOne of our best approaches so far has been to look for the effects of salt in the oceans on their electrical conductivity by studying magnetic fields around the moons. But these studies \u2018have mostly neglected all the other effects that generate magnetic fields,\u2019 said Professor Joachim Saur, a planetary scientist from the University of Cologne, Germany, such as thin atmospheres around the moons. \u2018It\u2019s very important to disentangle the effects that really come from the ocean.\u2019\u003C\/p\u003E\u003Cp\u003EProf. Saur is the project coordinator on \u003Ca href=\u0022https:\/\/cordis.europa.eu\/project\/id\/884711\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003EExo-Oceans\u003C\/a\u003E, which is hoping to answer this question. The project is using models and data from NASA\u2019s Galileo spacecraft, which orbited in the Jovian system from 1995 to 2003, along with measurements from NASA\u2019s Juno spacecraft currently at Jupiter and remote observations from telescopes like Hubble, to examine these oceans.\u003C\/p\u003E\u003Cp\u003E\u2018Our results will not overturn the idea of an ocean,\u2019 on Europa and Ganymede said Prof. Saur, although he noted they might question one on Callisto. But it\u2019s hoped they could give a better indication on things such as the thickness of the oceans, their salt content, and their distance from the icy sheets above.\u003C\/p\u003E\u003Cp\u003EAll this has important implications for the habitability of the moons. To be able to support life, it\u2019s thought the oceans need to be in contact with rock at the bottom in order for life to have a source of \u2018food\u2019, and currently only Europa is thought to meet that condition.\u003C\/p\u003E\u003Cp\u003E\u2018Europa is one of the best candidates for habitability because the liquid water is in direct contact with the silicate mantle,\u2019 said Prof. Saur. \u2018So there\u2019s a possibility of the leaching out of minerals from the crust into the ocean. And the richer it is in chemical compounds, the better it is for the evolution of life.\u2019\u003C\/p\u003E\u003Cp\u003EBut there\u2019s only so much that can be done before JUICE arrives. Once it does, its magnetometer instrument will provide useful measurements on the magnetic fields of the moons, giving us vital data on the oceans underneath. \u2018This will allow us to separate all the different effects,\u2019 said Prof. Saur.\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\u003E\u2018Europa is one of the best candidates for habitability because the liquid water is in direct contact with the silicate mantle.\u2019\u003C\/p\u003E\n \u003Cfooter\u003E\n \u003Ccite class=\u0022tw-not-italic tw-font-normal tw-text-sm tw-text-black\u0022\u003EProf. Joachim Saur, University of Cologne, Germany\u003C\/cite\u003E\n \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ERadiation\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EAnother important factor regarding the habitability of the moons is how much radiation from Jupiter is hitting them. Jupiter produces a lot of damaging radiation, so much that it can harm spacecraft that get too close.\u003C\/p\u003E\u003Cp\u003EOne way to study this is to observe aurorae on the moons, produced when charged particles from Jupiter hit magnetic fields around them. Europa, for example, has a constant aurora that \u003Ca href=\u0022https:\/\/eos.org\/research-spotlights\/hubble-gazes-at-europas-aurora\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Ecan be observed\u003C\/a\u003E in ultraviolet images from Hubble.\u003C\/p\u003E\u003Cp\u003E\u2018It relates to how the moon is exposed to this radiation because the charged particles from the radiation creates the aurora,\u2019 said Dr Lorenz Roth, a planetary astronomer and physicist from the KTH Royal Institute of Technology in Stockholm, Sweden. \u2018So it\u2019s kind of a measurement for how much radiation is there.\u2019\u003C\/p\u003E\u003Cp\u003EDr Roth worked on the\u0026nbsp;\u003Ca href=\u0022https:\/\/cordis.europa.eu\/project\/id\/800586\/reporting\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003EAuroraMHD\u003C\/a\u003E\u0026nbsp;project, which sought to use some of these auroral observations of Europa and Jupiter\u2019s volcanically active moon Io to learn more about them. While the project was hampered by the Covid-19 pandemic, it did provide some useful data.\u003C\/p\u003E\u003Cp\u003EIn particular, it helped confirm the existence of water plumes on Europa, and investigated how they interacted with its atmosphere. And it\u2019s hoped that this work can be built upon, with JUICE, to further study the habitability of Jupiter\u2019s icy moons.\u003C\/p\u003E\u003Cp\u003E\u2018The question of habitability and life always lingers in the background,\u2019 said Dr Roth. \u2018In all aspects, including size, the large Jupiter moons are like planets: they are similar to or bigger than Mercury, one has a magnetic field, they have atmospheres, they have oceans (and so on).\u003C\/p\u003E\u003Cp\u003E\u2018Europa is more promising (because its) water is very likely directly connected to the rocky material at the sea floor, which allows some reaction to take place.\u2019\u003C\/p\u003E\u003Cp\u003EJUICE will be equipped with its own ultraviolet instrument that could study the aurorae of the moons in more detail, helping scientists work out how Jupiter\u2019s radiation might impact their chances of life. \u2018Once JUICE is in orbit, we\u2019ll get a lot of information,\u2019 said Dr Roth. \u2018It can continuously measure the magnetic fields around the moons.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@alignleft@\u0022\u003E\n\u003Cimg alt=\u0022In 2022, ESA will launch a spacecraft called JUICE to explore Jupiter\u2019s moons, including Europa (left). Image credit - NASA, ESA, STScI, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley) and the OPAL team\u0022 height=\u00221663\u0022 src=\u0022\/research-and-innovation\/sites\/default\/files\/hm\/IMCEUpload\/stsci-h-p2042a-f-1663x1663.png\u0022 title=\u0022In 2022, ESA will launch a spacecraft called JUICE to explore Jupiter\u2019s moons, including Europa (left). Image credit - NASA, ESA, STScI, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley) and the OPAL team\u0022 width=\u00221663\u0022\u003E\n\u003Cfigcaption class=\u0022tw-italic tw-mb-4\u0022\u003EIn 2022, ESA will launch a spacecraft called JUICE to explore Jupiter\u2019s moons, including Europa (left). Image credit - NASA, ESA, STScI, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley) and the OPAL team\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EPotential habitability\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EBy itself, JUICE is not expected to tell us definitively if there is life on Jupiter\u2019s moons. But its data, along with NASA\u2019s \u003Ca href=\u0022https:\/\/www.jpl.nasa.gov\/missions\/europa-clipper\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003EEuropa Clipper mission\u003C\/a\u003E that will arrive in the Jovian system at a similar time to study Europa, could provide useful information on their potential habitability.\u003C\/p\u003E\u003Cp\u003EIn the same way that initial missions to Mars assessed its habitability, before later missions \u2013 like NASA\u2019s recently-landed Perseverance rover \u2013 were sent \u003Ca href=\u0022https:\/\/horizon-magazine.eu\/article\/how-life-earth-could-help-us-find-life-mars.html\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Eto look for life\u003C\/a\u003E, so too might similar research take place for Jupiter\u2019s moons.\u003C\/p\u003E\u003Cp\u003E\u2018While JUICE and the Europa Clipper have not even launched yet, there are already discussions about what could be next,\u2019 said Prof. Saur, such as landers using drills to go into the ice and sample these oceans. \u2018There is already work going on in parallel on what could be the next steps,\u2019 he said.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThe research in this article was funded by the EU. 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