Juno mission reveals unprecedented volcanic power on Io
The Juno mission has revealed exceptionally intense activity on Io, one of Jupiter's moons. Scientists from NASA's Juno mission cautioned that the hotspot is emitting eruptions with energy six times greater than the total power output of all power plants on Earth.
Even by Io's standards, the most volcanic celestial body in the Solar System, recent observations on this moon of Jupiter are extraordinary. Io is the third-largest natural satellite of Jupiter, and scientists have been captivated by it for a long time mainly because its size resembles our Moon. It is known as the most volcanically active body in the Solar System - it is covered by approximately 400 volcanoes, which eject lava and gases in almost continuous eruptions.
Eruptions of unimaginable power
Researchers from NASA's Juno mission have identified a massive volcanic area in the southern hemisphere of Io. This hot region is larger than Lake Superior on Earth and is emitting eruptions with power six times greater than the total energy generated by all power plants worldwide. This discovery was made possible by the Jovian Infrared Auroral Mapper (JIRAM) instrument, provided by the Italian Space Agency.
"Juno had two really close flybys of Io during Juno’s extended mission," said Scott Bolton, principal investigator from the Southwest Research Institute in San Antonio, quoted by NASA. He added, "And while each flyby provided data on the tormented moon that exceeded our expectations, the data from this latest — and more distant — flyby really blew our minds. This is the most powerful volcanic event ever recorded on the most volcanic world in our solar system — so that’s really saying something."
Io's volcanic activity results from its proximity to Jupiter. The gas giant orbits Io on an elliptical path, completing a full orbit every 42.5 hours. Variations in distance from Jupiter cause gravitational interactions that continuously compress Io. This results in gigantic thermal energy generated by friction, which melts the moon's interior and triggers continuous eruptions of lava and ash into the atmosphere from hundreds of volcanoes scattered across its surface.
Images of Io taken in 2024 by the Juno probe reveal significant surface changes around the moon's southern pole. These changes were observed between the 66th and 68th closest passes of Juno's orbit around Jupiter.
How has the surface of Jupiter's moon changed?
During the extended mission, Juno flies past Io every other orbit, each time over the same moon area. Earlier close flybys occurred in December 2023 and February 2024, when the probe approached 930 miles from Io's surface. The last flyby, on 27 December 2024, occurred from a distance of about 46,000 miles, with the JIRAM instrument focusing on the southern hemisphere of the moon.
Scientists estimate that this newly discovered area covers 39,000 square miles, surpassing the previous record-holder – Loki Patera, a lava lake with an area of 7,700 square miles. The total radiated power of this new hotspot exceeded 80 trillion watts.
Io in Fire
An eruption of this scale is likely to leave long-lasting traces. Previous significant eruptions on Io have led to various structures, such as pyroclastic deposits (composed of rock fragments ejected during eruptions), small lava flows fed by fissures, or particles rich in sulfur and sulfur dioxide.
