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- Jupiter\u2019s moon Io is the most volcanically active world<\/strong> in the entire solar system. It has at least 400 known active volcanoes. So, where does its magma come from?<\/li>\n
- There might be a subsurface global ocean of magma,<\/strong> scientists have theorized. Or is the magma in smaller pockets?<\/li>\n
- There is no global magma ocean<\/strong>, said a new study of data from NASA\u2019s Juno spacecraft. Instead, each volcano has its own localized pool of magma.<\/li>\n<\/ul>\n
The 2025 EarthSky lunar calendar makes a great gift. Get yours today!<\/p>\n
Io\u2019s raging volcanoes have their own magma power sources<\/h3>\n
Jupiter\u2019s moon Io is a world of volcanoes. In fact, it is the most volcanic body in the entire solar system. But how did it become that way? We know Jupiter\u2019s powerful gravitational pull heats Io\u2019s interior, melting rock and feeding the 400 known volcanoes. But is there a global ocean of magma beneath the surface? Or does each volcano have its own lava pool? Scientists with NASA\u2019s Juno mission said on December 12, 2024, that it\u2019s likely the latter. Io\u2019s raging volcanoes are self-powered.<\/p>\n
The researchers published their peer-reviewed paper in Nature<\/em> on December 12, 2024. While peer-reviewed and accepted for publication, the paper is a preview version and still undergoing editing.<\/p>\n
The results were also discussed at the American Geophysical Union\u2019s annual meeting this month in Washington, D.C.<\/p>\n
Does Io have a magma ocean?<\/h3>\n
With Io having so many volcanoes \u2013 at least 400 known \u2013 scientists theorized there might be a global ocean of magma beneath the surface. Many of the volcanoes are active at any given time, blasting lava and plumes into the extremely thin atmosphere. So there must be an on-going supply of magma below ground. Imaging scientist Linda Morabito at NASA\u2019s Jet Propulsion Laboratory (JPL) in California first saw signs of volcanic activity in Voyager 1 images in 1979.<\/p>\n
But is that magma global, or is it localized beneath each volcano?<\/p>\n
Scott Bolton is the principal investigator for the Juno mission. He said:<\/p>\n
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Since Morabito\u2019s discovery, planetary scientists have wondered how the volcanoes were fed from the lava underneath the surface. Was there a shallow ocean of white-hot magma fueling the volcanoes, or was their source more localized? We knew data from Juno\u2019s two very close flybys could give us some insights on how this tortured moon actually worked.<\/p>\n<\/blockquote>\n
So, does Io have a magma ocean? The answer appears to be no.<\/p>\n
![\"Red](\"https:\/\/earthsky.org\/upl\/2024\/12\/Io-volcanoes-infrared-Juno-July-5-2022.jpg\")
View larger. | NASA\u2019s Juno spacecraft captured this stunning infrared view of Io and its many volcanoes on July 5, 2022. Image via NASA\/ JPL-Caltech\/ SwRI\/ ASI\/ INAF\/ JIRAM.<\/figcaption><\/figure>\n Io\u2019s raging volcanoes are self-powered<\/h3>\n
Juno, which orbits Jupiter, made extremely close flybys of Io in December 2023 and February 2024. It came within 930 miles (1,500 km) of the scorched and roiling surface. Juno measured Io\u2019s gravity by calculating how it affected the spacecraft\u2019s acceleration. This can provide clues about the moon\u2019s interior.<\/p>\n
Io experiences what scientists call tidal flexing, or tidal heating. That\u2019s due to Jupiter\u2019s gravity squeezing and pulling on Io\u2019s insides. This creates heat and melts subsurface rock, forming magma. The scientists wanted to know if that subsurface magma was global or just under each volcano. Bolton explained:<\/p>\n
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This constant flexing creates immense energy, which literally melts portions of Io\u2019s interior. If Io has a global magma ocean, we knew the signature of its tidal deformation would be much larger than a more rigid, mostly solid interior. Thus, depending on the results from Juno\u2019s probing of Io\u2019s gravity field, we would be able to tell if a global magma ocean was hiding beneath its surface.<\/p>\n<\/blockquote>\n
The results suggested that Io does not<\/em> have a global magma ocean. The deformation of Io\u2019s interior from the tidal flexing did not match what would be expected from a global layer of magma. Instead, each volcano is self-powered with its own localized pool of magma.<\/p>\n
- There might be a subsurface global ocean of magma,<\/strong> scientists have theorized. Or is the magma in smaller pockets?<\/li>\n