The most intense volcanic eruption ever seen on a celestial body has been recorded by NASA’s Juno spacecraft, as detected during a flyby on December 27, 2024. During this flyby, Juno’s Jovian Infrared Auroral Mapper detected an enormous hotspot in Io’s southern hemisphere. It was found that the released energy is about 80 trillion watts and thus six times higher than the total of all power plants put together on Earth.
Io: the most volcanically active body in the solar system
Io is the innermost of Jupiter’s four Galilean moons, and it holds the title of being the most volcanically active body in the solar system. The moon’s extreme geological activity arises due to tidal heating; this is caused by the extremely strong gravitational pull of the gas giant. This continuous flexing generates internal heat, leading to frequent and violent volcanic eruptions.
Juno’s Discovery: A Gigantic New Hotspot
Juno’s JIRAM instrument captured newly created volcanic hotspots, this one measuring a newly formed area around 105,000 square kilometers in size and thus it has been recognized to be the biggest volcanic hot spot ever identified in Io. Compared to another huge volcanic area well known by all as the Loki Patera lava lake at around 21,000 square kilometers. So, an extended underground magma reservoir must feed the huge feature in the subsurface.
NASA scientists were quite surprised by how massive this event was. In fact, mission lead scientist Juno Scott Bolton said the vigor of this volcano was far in excess of the scientists’ greatest expectations. Such a violent release of volcanic gas and material represents the most spectacular volcanic eruption outburst yet discovered on Io, he added
Images taken by Juno during the flyby revealed a large, darkened region on Io’s surface. Scientists believe this area is covered by fresh lava flows from the eruption. However, due to the spacecraft’s distance during the flyby, high-resolution images were not obtained. Future observations are expected to provide a clearer picture of how the eruption has reshaped Io’s surface.
Understanding Io’s Volcanism
Unlike Earth, whose volcanic eruptions are driven from the interior by heat from a molten core, the volcanism on Io is externally driven by gravitational forces. The huge pull of Jupiter and its neighbours Europa and Ganymede produces intense tidal stresses that constantly deform the moon inside and cause heating. This deep heating leads to huge reservoirs of magma below the crust of this moon.
Earlier theories suggested that Io’s interior was composed entirely of molten magma, but recent research indicates that magma is concentrated in localized reservoirs, such as the newly identified hotspot. The latest eruption further supports this theory, highlighting Io’s complex and dynamic geology.
Upcoming Flyby to Gather More Data
NASA has planned another close flyby of Io for March 3, 2025, at which time Juno will try to capture even more detailed data on the newly discovered volcanic hotspot. Scientists are hoping that the closer approach will reveal further insights into Io’s volcanic mechanisms and provide a better understanding of how tidal heating shapes planetary bodies throughout the solar system.
Juno mission scientist Scott Bolton said that this is not only a record-breaking event but also an important opportunity to improve our knowledge of volcanic activity beyond Earth. Scientists expect that further observations will deepen our understanding of tidal heating processes and their role in shaping celestial bodies.
This detection of an unprecedented volcanic eruption on Io marks a new milestone in planetary science. Io continues to surprise scientists with extreme geological activity, and future missions and observations will be essential to unraveling the mysteries of this volcanically hyperactive moon.