{"id":196055,"date":"2025-09-03T05:51:09","date_gmt":"2025-09-03T05:51:09","guid":{"rendered":"https:\/\/www.europesays.com\/us\/196055\/"},"modified":"2025-09-03T05:51:09","modified_gmt":"2025-09-03T05:51:09","slug":"juno-detected-the-final-missing-auroral-signature-from-jupiters-four-largest-moons","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/196055\/","title":{"rendered":"Juno Detected the Final Missing Auroral Signature from Jupiter\u2019s Four Largest Moons"},"content":{"rendered":"<p>Jupiter hosts the brightest and most spectacular auroras in the Solar System. Near its poles, these shimmering lights offer a glimpse into how the planet interacts with the solar wind and moons swept by Jupiter\u2019s magnetic field. Unlike Earth\u2019s northern lights, the largest moons of Jupiter create their own auroral signatures in the planet\u2019s atmosphere \u2014 a phenomenon that Earth\u2019s Moon does not produce. These moon-induced auroras, known as \u201csatellite footprints,\u201d reveal how each moon interacts with its local space environment.<\/p>\n<p>Before NASA\u2019s Juno mission, three of Jupiter\u2019s four largest moons, known as Galilean moons \u2014 Io, Europa, and Ganymede \u2014 were shown to produce these distinct auroral signatures. But Callisto, the most distant of the Galilean moons, remained a mystery. Despite multiple attempts using <a href=\"https:\/\/science.nasa.gov\/mission\/hubble\/science\/science-highlights\/studying-the-planets-and-moons\/\" target=\"_blank\" rel=\"noopener\">NASA\u2019s Hubble Space Telescope<\/a>, Callisto\u2019s footprint had proven elusive, both because it is faint and because it most often lies atop the brighter main auroral oval, the region where auroras are displayed.<\/p>\n<p><a href=\"https:\/\/science.nasa.gov\/mission\/juno\/\" target=\"_blank\" rel=\"noopener\">NASA\u2019s Juno mission<\/a>, orbiting Jupiter since 2016, offers unprecedented close-up views of these polar light shows. But to image Callisto\u2019s footprint, the main auroral oval needs to move aside while the polar region is being imaged. And to bring to bear Juno\u2019s arsenal of instruments studying fields and particles, the spacecraft&#8217;s trajectory must carry it across the magnetic field line linking Callisto and Jupiter.\u00a0<\/p>\n<p>These two events serendipitously occurred during Juno\u2019s 22nd orbit of the giant planet, in September 2019, revealing Callisto\u2019s auroral footprint and providing a sample of the particle population, electromagnetic waves, and magnetic fields associated with the interaction.\u00a0<\/p>\n<p>Jupiter\u2019s magnetic field extends far beyond its major moons, carving out a vast region (magnetosphere) enveloped by, and buffeted by, the solar wind streaming from our Sun. Just as solar storms on Earth push the northern lights to more southern latitudes, Jupiter\u2019s auroras are also affected by our Sun\u2019s activity. In September 2019, a massive, high-density solar stream buffeted Jupiter\u2019s magnetosphere, briefly revealing \u2014 as the auroral oval moved toward Jupiter\u2019s equator \u2014 a faint but distinct signature associated with Callisto. This discovery finally confirms that all four Galilean moons leave their mark on Jupiter\u2019s atmosphere, and that Callisto\u2019s footprints are sustained much like those of its siblings, completing the family portrait of the Galilean moon auroral signatures.<\/p>\n<p>An international team of scientists led by Jonas Rabia of the Institut de Recherche en Astrophysique et Plan\u00e9tologie (IRAP), CNRS, CNES, in Toulouse, France, published their paper on the discovery, <a href=\"https:\/\/rdcu.be\/eDLsI\" target=\"_blank\" rel=\"noopener\">\u201cIn situ and remote observations of the ultraviolet footprint of the moon Callisto by the Juno spacecraft,\u201d<\/a> in the journal Nature Communications on Sept. 1, 2025.<\/p>\n","protected":false},"excerpt":{"rendered":"Jupiter hosts the brightest and most spectacular auroras in the Solar System. Near its poles, these shimmering lights&hellip;\n","protected":false},"author":3,"featured_media":196056,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[54810,109028,12975,12976,71240,159,783,67,132,68],"class_list":{"0":"post-196055","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-auroras","9":"tag-callisto","10":"tag-juno","11":"tag-jupiter","12":"tag-jupiter-moons","13":"tag-science","14":"tag-space","15":"tag-united-states","16":"tag-unitedstates","17":"tag-us"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/115138808007887710","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/196055","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=196055"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/196055\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/196056"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=196055"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=196055"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=196055"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}