Jupiter’s moon Io is covered in hundreds of volcanoes, which spew fountains of lava that constantly refill impact craters on its surface with scorching molten lakes. A recent discovery of extreme volcanic activity on the Jovian moon tops any eruption previously detected on Io, proving that this chaotic world knows no bounds.

NASA’s Juno mission detected a volcanic hot spot in the southern hemisphere of Jupiter’s moon, marking the most energetic eruption ever detected on Io or anywhere else in the solar system beyond Earth The volcanic hot spot spans 40,000 square miles (100,000 square kilometers), erupting with six times the amount of energy produced by all of the world’s power plants combined.

“This is the most powerful volcanic event ever recorded on the most volcanic world in our solar system—so that’s really saying something,” Scott Bolton, a researcher at the Southwest Research Institute in San Antonio and principal investigator of the Juno mission, said in a statement.

Details of the discovery were recently published in the Journal of Geophysical Research: Planets.

Fountain of lava

Juno has been orbiting Jupiter for nearly a decade. The spacecraft’s extended mission, which began in 2021, has allowed scientists to study Jupiter’s moons Io, Europa, Ganymede, and Callisto.

Juno flies over the same region of Io once every two orbits. During its latest flyby on December 27, 2024, the spacecraft flew to within about 46,200 miles (74,400 kilometers) of the moon and focused its infrared instrument on the southern hemisphere.

Using Juno’s Jovian Infrared Auroral Mapper (JIRAM) instrument, contributed by the Italian Space Agency, scientists detected an event of extreme infrared radiance. The total power value of the new hot spot’s radiance measured well above 80 trillion watts.

“What makes the event even more extraordinary is that it did not involve a single volcano, but multiple active sources that lit up simultaneously, increasing their brightness by more than a thousand times compared to typical levels,” Alessandro Mura, a researcher at the Italian National Institute for Astrophysics (INAF), and lead author of the paper, said in an emailed statement. “This perfect synchrony suggests that it was a single enormous eruptive event, propagating through the subsurface for hundreds of kilometers.”

The data not only suggests that this is the most intense volcanic eruption ever recorded on Io, it also hints that there’s a massive chamber system of interconnected magma reservoirs beneath the moon’s surface. This interwoven system can be activated simultaneously to produce a single, planetary-wide energy release. “We have evidence what we detected is actually a few closely spaced hot spots that emitted at the same time,” Mura said.

JunoCam, the spacecraft’s visible light camera, also captured the event. The team compared images captured by JunoCam from the mission’s last two flybys of Io in April and October of 2024 with the latest ones taken in December 2024, discovering significant changes in the surface coloring around the area where the hot spot was detected.

Tormented world

Io’s volcanic activity is the result of a gravitational tug-of-war between Jupiter’s gravitational pull on the moon and precisely timed pulls from neighboring moons Ganymede and Europa. The tortured moon is the subject of extreme tidal forces, causing its surface to bulge up and down by as much as 330 feet (100 meters) at a time, according to NASA.

The tidal forces generate a tremendous amount of heat within Io, thereby causing its liquid subsurface crust to seek relief from the pressure by escaping to the surface. The surface of Io is constantly being renewed, as molten lava refills the moon’s impact craters, smoothing out the moon with fresh liquid rock.

The recently detected eruption will likely leave a long-lasting impact on Io. The team behind Juno will use the mission’s upcoming flyby of the moon on March 3 to look at the hot spot again and make note of any changes to the landscape surrounding it.

“While it is always great to witness events that rewrite the record books, this new hot spot can potentially do much more,” Bolton said. “The intriguing feature could improve our understanding of volcanism not only on Io but on other worlds as well.”