{"id":710,"date":"2026-07-23T09:32:00","date_gmt":"2026-07-23T00:32:00","guid":{"rendered":"https:\/\/onepress.co.kr\/index.php\/briefing\/2026-07-23-juno-io-subsurface-heat-en\/"},"modified":"2026-07-23T09:32:00","modified_gmt":"2026-07-23T00:32:00","slug":"2026-07-23-juno-io-subsurface-heat-en","status":"publish","type":"briefing","link":"https:\/\/onepress.co.kr\/index.php\/briefing\/2026-07-23-juno-io-subsurface-heat-en\/","title":{"rendered":"NASA\u2019s Juno has measured heat a few metres below Io\u2019s surface"},"content":{"rendered":"<p><strong>2026-07-23 09:26 KST<\/strong><\/p>\n<p>NASA JPL said on 22 July 2026 that the Juno spacecraft made the first measurements of temperatures below the surface of Jupiter\u2019s moon Io. The key point is not another volcano image, but microwave evidence that can help separate global interior heating from young lava flows cooling beneath a thin crust.<\/p>\n<h2>What Juno Observed<\/h2>\n<p>Juno passed close to Io on 30 December 2023 and 3 February 2024, coming within about 930 miles or 1,500 kilometres. JPL says its Microwave Radiometer detected temperatures rising by more than 40 Fahrenheit degrees just a few feet below the surface. NASA Photojournal describes related microwave channels as probing roughly 6 to 20 feet, or 2 to 6 metres, into the crust.<\/p>\n<h2>Why It Is New<\/h2>\n<p>Io is known as the most volcanically active body in the Solar System, but many observations focus on eruptions and hot spots at the surface. These measurements begin to show how heat is distributed below that surface. That helps test whether tidal heating is spread broadly through Io or whether the signal comes from young lava flows cooling under a shallow crust.<\/p>\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/onepress.co.kr\/wp-content\/uploads\/2026\/07\/juno-io-subsurface-heat-en.png\" alt=\"Space-exploration concept image of Juno using microwaves to probe heat below Io surface\" loading=\"eager\" \/><figcaption class=\"op-briefing-image-caption\">Produced image: ONEPRESS illustrates Juno microwave observations probing thermal layers below Io\u2019s surface. It is not a spacecraft photograph or observation frame.<\/figcaption><\/figure>\n<h2>Two Possible Readings<\/h2>\n<p>One JPL interpretation is a background heat flow of 1 to 3 watts per square metre, as much as 30 times Earth\u2019s average. Another is that cooling lava flows lie under a 30 to 35 foot, or 9 to 11 metre, crust across about 10% of Io\u2019s surface. Either way, the observation gives a new handle on how internal heat reaches shallow layers.<\/p>\n<h2>Limits And Next Research<\/h2>\n<p>The result comes from two Juno close passes and specific microwave channels. Distinguishing global heat flow from broad young lava fields will require comparison with terrain, infrared data, and records of volcanic activity. The best reading is that scientists have begun directly probing Io\u2019s subsurface heat, not that they have fully mapped its interior.<\/p>\n<h2>Official sources<\/h2>\n<p><a href=\"https:\/\/www.jpl.nasa.gov\/news\/nasas-juno-takes-temperature-of-jupiters-fiery-moon-io\/\" target=\"_blank\" rel=\"noopener noreferrer\">NASA JPL release: flybys, temperature rise, and interpretations<\/a><\/p>\n<p><a href=\"https:\/\/science.nasa.gov\/photojournal\/nasas-juno-peers-beneath-ios-surface\/\" target=\"_blank\" rel=\"noopener noreferrer\">NASA Photojournal: microwave depth and image context<\/a><\/p>\n<p><a href=\"https:\/\/agupubs.onlinelibrary.wiley.com\/doi\/10.1029\/2025JE009622\" target=\"_blank\" rel=\"noopener noreferrer\">JGR Planets paper: observational analysis and science conditions<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>NASA JPL said on 22 July 2026 that the Juno spacecraft made the first measurements of temperatures below the surface of Jupiter\u2019s moon Io. The key point is not another volcano image, but microwave evidence that can help separate global interior heating from young lava flows cooling beneath a thin crust.<\/p>\n","protected":false},"featured_media":0,"template":"","meta":[],"class_list":["post-710","briefing","type-briefing","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/onepress.co.kr\/index.php\/wp-json\/wp\/v2\/briefing\/710","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/onepress.co.kr\/index.php\/wp-json\/wp\/v2\/briefing"}],"about":[{"href":"https:\/\/onepress.co.kr\/index.php\/wp-json\/wp\/v2\/types\/briefing"}],"wp:attachment":[{"href":"https:\/\/onepress.co.kr\/index.php\/wp-json\/wp\/v2\/media?parent=710"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}