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Ice volcanoes on Ganymede? New promising candidates found

May 21, 2026
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View larger. | Jupiter’s moon Ganymede is the largest moon in our solar system. Are there ice volcanoes on Ganymede? It’s possible, and now a new study has identified several good candidates. NASA’s Juno spacecraft captured this view of Ganymede on June 7, 2021. Image via NASA/ JPL-Caltech/ SwRI/ MSSS/ Kalleheikki Kannisto.
  • Ganymede is Jupiter’s largest moon. It has a deep ocean beneath its outer icy surface. Does it also have ice volcanoes?
  • A new international study has identified several good candidates on Ganymede’s frozen surface.
  • These are depressions in the surface surrounded by flow-like formations, where water could have erupted to the surface from below.

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Possible ice volcanoes on Ganymede

Does Jupiter’s largest moon Ganymede have ice volcanoes? We don’t know for sure yet, but a new international study has identified some promising candidates.

Ganymede has a deep ocean hidden beneath its icy crust. That’s led scientists to speculate it could have ice volcanoes similar to the explosive geysers on Saturn’s ocean moon Enceladus. And on May 9, 2026, researchers said they have identified four primary locations where water and other volatile materials might have erupted to Ganymede’s surface.

Anezina Solomonidou at the Hellenic Space Center (HSC) in Greece led the new study. The study also includes researchers from France, Italy, Germany, the United States, the Czech Republic, ESA and NASA’s Jet Propulsion Laboratory.

The new peer-reviewed paper is accepted for publication in the Planetary Science Journal.

Gray landscape seen from above, with an oblong depression, craters and linear grooves.
Musa Patera, a depression on Ganymede some 43 miles (69 km) across. Scientists think it could have been left by an erupting ice volcano. NASA’s Galileo spacecraft captured this view on May 7, 1997. Image via NASA/ JPL/ Wikipedia.
Moon-like gray body with rayed crater and bright and dark patches.
View larger. | Another view of Jupiter’s largest moon Ganymede, from the Juno flyby on June 7, 2021. Image via NASA/ JPL-Caltech/ SwRI/ MSSS; image processing by Kevin M. Gill.

Most promising locations for ice volcanoes

Ganymede has unusual depressions – called paterae – and flow-like structures on its surface. Could upwelling water have formed them?

It certainly seems possible, since Ganymede has a deep, dark ocean beneath its outer icy crust. But it depends on whether the water could get through the crust in cracks or by other means. Scientists estimate Ganymede’s crust to be about 90-95 miles (145-153 km) thick. And they estimate the ocean below to be 60 miles (96 km) deep.

Intriguingly, the flow-like structures would have been formed by flowing icy watery material. And the paterae depressions would have been the volcanic vents. It’s similar to regular volcanism, but involving icy fluids rather than molten rock.

Sunlit edge of planet-like body, with geyser-like jets of vapor erupting upward against a black background.
View larger. | Saturn’s ocean moon Enceladus is famous for its geyser-like ice volcanoes. NASA’s Cassini spacecraft took this image on November 21, 2009. Does Ganymede have ice volcanoes too? Image via NASA/ JPL-Caltech/ Space Science Institute.

Implications for life

If there were – or perhaps still are – active ice volcanoes on Ganymede, that could provide clues about the conditions in the ocean below. And those conditions could determine whether Ganymede’s ocean might be habitable or not.

Solomonidou said:

Ganymede is one of the most fascinating worlds in the solar system. Understanding possible cryovolcanic activity can help us better understand how ocean worlds evolve and whether they may host conditions suitable for life.

Young woman with long, curly dark-gold hair standing with her arms folded.
Anezina Solomonidou at the Hellenic Space Center in Greece led the new study about ice volcanoes on Ganymede. Image via Hellenic Space Center.

Future observations by JUICE

The candidate ice volcanoes will be of great interest for the European Space Agency’s upcoming Jupiter Icy Moons Explorer (JUICE) mission. JUICE was launched in 2023 and will arrive at Jupiter in 2031. It will focus on exploring the largest moons of Jupiter: Ganymede, Callisto, Io and Europa. JUICE will use its MAJIS imaging spectrometer and the JANUS camera system to take a closer look at these potential ice volcanoes.

In 2023, scientists found that Ganymede is coated in salts and organics; and in 2021, they found water vapor in Ganymede’s thin atmosphere.

Also in 2021, NASA released new closeups of Ganymede from its Juno spacecraft. Juno obtained the images on June 7, 2021.

Bottom line: Are there ice volcanoes on Ganymede? A new international study reveals several good candidates on Jupiter’s large ocean moon.

Via Hellenic Space Center

Read more: Jupiter’s moon Ganymede is coated in salts and organics

Read more: Why do Jupiter’s large moons outnumber Saturn’s?

Paul Scott Anderson

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About the Author:

Paul Scott Anderson has had a passion for space exploration that began when he was a child when he watched Carl Sagan’s Cosmos. He studied English, writing, art and computer/publication design in high school and college. He later started his blog The Meridiani Journal in 2005, which was later renamed Planetaria. He also later started the blog Fermi Paradoxica, about the search for life elsewhere in the universe.

While interested in all aspects of space exploration, his primary passion is planetary science and SETI. In 2011, he started writing about space on a freelance basis with Universe Today. He has also written for SpaceFlight Insider and AmericaSpace and has also been published in The Mars Quarterly. He also did some supplementary writing for the iOS app Exoplanet.

He has been writing for EarthSky since 2018, and also assists with proofing and social media.



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