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Preparations for Next Moonwalk Simulations Underway (and Underwater)<\/h1>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n![\"A](\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2025\/01\/1-pia26527-io-eruption-ir-final.jpg?w=2048\")
<\/a><\/figure>\nA massive hotspot \u2014 larger the Earth\u2019s Lake Superior \u2014 can be seen just to the right of Io\u2019s south pole in this annotated image taken by the JIRAM infrared imager aboard NASA\u2019s Juno on Dec. 27, 2024, during the spacecraft\u2019s flyby of the Jovian moon. <\/div>\nNASA\/JPL-Caltech\/SwRI\/ASI\/INAF\/JIRAM<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nEven by the standards of Io, the most volcanic celestial body in the solar system, recent events observed on the Jovian moon are extreme.<\/em><\/p>\nScientists with NASA\u2019s Juno mission have discovered a volcanic hot spot in the southern hemisphere of Jupiter\u2019s moon Io. The hot spot is not only larger than Earth\u2019s Lake Superior, but it also belches out eruptions six times the total energy of all the world\u2019s power plants. The discovery of this massive feature comes courtesy of Juno\u2019s Jovian Infrared Auroral Mapper (JIRAM) instrument, contributed by the Italian Space Agency.<\/p>\n
\u201cJuno had two really close flybys of Io during Juno\u2019s extended mission<\/a>,\u201d said the mission\u2019s principal investigator, Scott Bolton of the Southwest Research Institute in San Antonio. \u201cAnd while each flyby provided data on the tormented moon that exceeded our expectations, the data from this latest \u2014 and more distant \u2014 flyby really blew our minds. This is the most powerful volcanic event ever recorded on the most volcanic world in our solar system \u2014 so that\u2019s really saying something.\u201d<\/p>\nThe source of Io\u2019s torment: Jupiter. About the size of Earth\u2019s Moon, Io is extremely close to the mammoth gas giant, and its elliptical orbit whips it around Jupiter once every 42.5 hours. As the distance varies, so does the planet\u2019s gravitational pull, which leads to the moon being relentlessly squeezed. The result: immense energy from frictional heating that melts portions of Io\u2019s interior, resulting in a seemingly endless series of lava plumes and ash venting into its atmosphere from the estimated 400 volcanoes that riddle its surface.<\/p>\n
Close Flybys<\/strong><\/h3>\nDesigned to capture the infrared light (which isn\u2019t visible to the human eye) emerging from deep inside Jupiter, JIRAM probes the gas giant\u2019s weather layer, peering 30 to 45 miles (50 to 70 kilometers) below its cloud tops. But since NASA extended Juno\u2019s mission, the team has also used the instrument to study the moons Io<\/a>, Europa<\/a>, Ganymede<\/a>, and Callisto.<\/p>\n\n\n\n![\"Images](\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2025\/01\/e-pia26526-io-eruption-junocam.jpg?w=2048\")
<\/a><\/figure>\nImages of Io captured in 2024 by the JunoCam imager aboard NASA\u2019s Juno show signif-icant and visible surface changes (indicated by the arrows) near the Jovian moon\u2019s south pole. These changes occurred between the 66th and 68th perijove, or the point during Juno\u2019s orbit when it is closest to Jupiter.<\/div>\nImage data: NASA\/JPL-Caltech\/SwRI\/MSSS Image processing by Jason Perry<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nDuring its extended mission, Juno\u2019s trajectory passes by Io every other orbit, flying over the same part of the moon each time. Previously, the spacecraft made close flybys of Io in December 2023<\/a> and February 2024<\/a>, getting within about 930 miles (1,500 kilometers) of its surface. The latest flyby took place on Dec. 27, 2024, bringing the spacecraft within about 46,200 miles (74,400 kilometers) of the moon, with the infrared instrument trained on Io\u2019s southern hemisphere.<\/p>\nIo Brings the Heat<\/strong><\/strong><\/h3>\n\u201cJIRAM detected an event of extreme infrared radiance \u2014 a massive hot spot \u2014 in Io\u2019s southern hemisphere so strong that it saturated our detector,\u201d said Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics in Rome. \u201cHowever, we have evidence what we detected is actually a few closely spaced hot spots that emitted at the same time, suggestive of a subsurface vast magma chamber system. The data supports that this is the most intense volcanic eruption ever recorded on Io.\u201d<\/p>\n
The JIRAM science team estimates the as-yet-unnamed feature spans 40,000 square miles (100,000 square kilometers). The previous record holder was Io\u2019s Loki Patera<\/a>, a lava lake of about 7,700 square miles (20,000 square kilometers). The total power value of the new hot spot\u2019s radiance measured well above 80 trillion watts.<\/p>\nPicture This<\/strong><\/h3>\nThe feature was also captured by the mission\u2019s JunoCam visible light camera. The team compared JunoCam images from the two previous Io flybys with those the instrument collected on Dec. 27. And while these most recent images are of lower resolution since Juno was farther away, the relative changes in surface coloring around the newly discovered hot spot were clear. Such changes in Io\u2019s surface are known in the planetary science community to be associated with hot spots and volcanic activity.<\/p>\n
An eruption of this magnitude is likely to leave long-lived signatures. Other large eruptions on Io have created varied features, such as pyroclastic deposits (composed rock fragments spewed out by a volcano), small lava flows that may be fed by fissures, and volcanic-plume deposits rich in sulfur and sulfur dioxide.<\/p>\n
Juno will use an upcoming, more distant flyby of Io on March 3 to look at the hot spot again and search for changes in the landscape. Earth-based observations of this region of the moon may also be possible. \u00a0<\/p>\n
\u201cWhile it is always great to witness events that rewrite the record books, this new hot spot can potentially do much more,\u201d said Bolton. \u201cThe intriguing feature could improve our understanding of volcanism not only on Io but on other worlds as well.\u201d<\/p>\n
More About Juno<\/h3>\n
NASA\u2019s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of the Southwest Research Institute in San Antonio. Juno is part of NASA\u2019s New Frontiers Program, which is managed at NASA\u2019s Marshall Space Flight Center in Huntsville, Alabama, for the agency\u2019s Science Mission Directorate in Washington. The Italian Space Agency (ASI) funded the Jovian InfraRed Auroral Mapper. Lockheed Martin Space in Denver built and operates the spacecraft. Various other institutions around the U.S. provided several of the other scientific instruments on Juno.<\/p>\n
More information about Juno is available at:<\/p>\n
https:\/\/www.nasa.gov\/juno<\/a><\/p>\nNews Media Contacts<\/h3>\n
DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov<\/a><\/p>\nKaren Fox \/ Alana Johnson
NASA Headquarters, Washington
202-358-1600 \/ 202-358-1501
karen.c.fox@nasa.gov<\/a> \/ alana.r.johnson@nasa.gov<\/a><\/p>\nDeb Schmid
Southwest Research Institute, San Antonio
210-522-2254
dschmid@swri.org<\/a><\/p>\n2025-010 \u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n
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![\"A](\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2025\/01\/1-pia26527-io-eruption-ir-final.jpg\")
<\/a><\/figure>Even by the standards of Io, the most volcanic celestial body in the solar system, recent events observed on the Jovian moon are extreme.<\/em><\/p>\n Scientists with NASA\u2019s Juno mission have discovered a volcanic hot spot in the southern hemisphere of Jupiter\u2019s moon Io. The hot spot is not only larger than Earth\u2019s Lake Superior, but it also belches out eruptions six times the total energy of all the world\u2019s power plants. The discovery of this massive feature comes courtesy of Juno\u2019s Jovian Infrared Auroral Mapper (JIRAM) instrument, contributed by the Italian Space Agency.<\/p>\n \u201cJuno had two really close flybys of Io during Juno\u2019s extended mission<\/a>,\u201d said the mission\u2019s principal investigator, Scott Bolton of the Southwest Research Institute in San Antonio. \u201cAnd while each flyby provided data on the tormented moon that exceeded our expectations, the data from this latest \u2014 and more distant \u2014 flyby really blew our minds. This is the most powerful volcanic event ever recorded on the most volcanic world in our solar system \u2014 so that\u2019s really saying something.\u201d<\/p>\n The source of Io\u2019s torment: Jupiter. About the size of Earth\u2019s Moon, Io is extremely close to the mammoth gas giant, and its elliptical orbit whips it around Jupiter once every 42.5 hours. As the distance varies, so does the planet\u2019s gravitational pull, which leads to the moon being relentlessly squeezed. The result: immense energy from frictional heating that melts portions of Io\u2019s interior, resulting in a seemingly endless series of lava plumes and ash venting into its atmosphere from the estimated 400 volcanoes that riddle its surface.<\/p>\n Designed to capture the infrared light (which isn\u2019t visible to the human eye) emerging from deep inside Jupiter, JIRAM probes the gas giant\u2019s weather layer, peering 30 to 45 miles (50 to 70 kilometers) below its cloud tops. But since NASA extended Juno\u2019s mission, the team has also used the instrument to study the moons Io<\/a>, Europa<\/a>, Ganymede<\/a>, and Callisto.<\/p>\n During its extended mission, Juno\u2019s trajectory passes by Io every other orbit, flying over the same part of the moon each time. Previously, the spacecraft made close flybys of Io in December 2023<\/a> and February 2024<\/a>, getting within about 930 miles (1,500 kilometers) of its surface. The latest flyby took place on Dec. 27, 2024, bringing the spacecraft within about 46,200 miles (74,400 kilometers) of the moon, with the infrared instrument trained on Io\u2019s southern hemisphere.<\/p>\n \u201cJIRAM detected an event of extreme infrared radiance \u2014 a massive hot spot \u2014 in Io\u2019s southern hemisphere so strong that it saturated our detector,\u201d said Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics in Rome. \u201cHowever, we have evidence what we detected is actually a few closely spaced hot spots that emitted at the same time, suggestive of a subsurface vast magma chamber system. The data supports that this is the most intense volcanic eruption ever recorded on Io.\u201d<\/p>\n The JIRAM science team estimates the as-yet-unnamed feature spans 40,000 square miles (100,000 square kilometers). The previous record holder was Io\u2019s Loki Patera<\/a>, a lava lake of about 7,700 square miles (20,000 square kilometers). The total power value of the new hot spot\u2019s radiance measured well above 80 trillion watts.<\/p>\n The feature was also captured by the mission\u2019s JunoCam visible light camera. The team compared JunoCam images from the two previous Io flybys with those the instrument collected on Dec. 27. And while these most recent images are of lower resolution since Juno was farther away, the relative changes in surface coloring around the newly discovered hot spot were clear. Such changes in Io\u2019s surface are known in the planetary science community to be associated with hot spots and volcanic activity.<\/p>\n An eruption of this magnitude is likely to leave long-lived signatures. Other large eruptions on Io have created varied features, such as pyroclastic deposits (composed rock fragments spewed out by a volcano), small lava flows that may be fed by fissures, and volcanic-plume deposits rich in sulfur and sulfur dioxide.<\/p>\n Juno will use an upcoming, more distant flyby of Io on March 3 to look at the hot spot again and search for changes in the landscape. Earth-based observations of this region of the moon may also be possible. \u00a0<\/p>\n \u201cWhile it is always great to witness events that rewrite the record books, this new hot spot can potentially do much more,\u201d said Bolton. \u201cThe intriguing feature could improve our understanding of volcanism not only on Io but on other worlds as well.\u201d<\/p>\n NASA\u2019s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of the Southwest Research Institute in San Antonio. Juno is part of NASA\u2019s New Frontiers Program, which is managed at NASA\u2019s Marshall Space Flight Center in Huntsville, Alabama, for the agency\u2019s Science Mission Directorate in Washington. The Italian Space Agency (ASI) funded the Jovian InfraRed Auroral Mapper. Lockheed Martin Space in Denver built and operates the spacecraft. Various other institutions around the U.S. provided several of the other scientific instruments on Juno.<\/p>\n More information about Juno is available at:<\/p>\n https:\/\/www.nasa.gov\/juno<\/a><\/p>\n DC Agle Karen Fox \/ Alana Johnson Deb Schmid 2025-010 \u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\nClose Flybys<\/strong><\/h3>\n
<\/a><\/figure>Io Brings the Heat<\/strong><\/strong><\/h3>\n
Picture This<\/strong><\/h3>\n
More About Juno<\/h3>\n
News Media Contacts<\/h3>\n
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov<\/a><\/p>\n
NASA Headquarters, Washington
202-358-1600 \/ 202-358-1501
karen.c.fox@nasa.gov<\/a> \/ alana.r.johnson@nasa.gov<\/a><\/p>\n
Southwest Research Institute, San Antonio
210-522-2254
dschmid@swri.org<\/a><\/p>\nShare<\/h2>\n<\/p><\/div>\n