2.5 times the size of the Sea of Azov: Juno detects record eruption on Io

Juno has discovered a record hot spot in the Southern Hemisphere of Jupiter’s moon Io. Its area is 2.5 times larger than the Sea of Azov.

Volcanic eruption on Io. Source: NASA

Io is the most geologically active body in the Solar System. Its surface is covered with hundreds of continuously erupting volcanoes. The main source of their activity is Jupiter. Io moves in an elliptical orbit around the gas giant, making one orbit around it in 42.5 hours. As the distance changes, the gravitational pull of the planet also changes, causing the moon to be constantly compressed. This process releases tremendous energy that melts Io’s interior, leading to endless eruptions.

Until recently, Io’s largest hot spot was Loki Patera: a 20,000 km2 lava lake. But now scientists have discovered a much larger object.

Infrared radiation from a hot spot detected by Juno at Io’s south pole. Source: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

The discovery was made during two very close flybys of Io by Juno. They took place in December 2023 and February 2024. As part of their work, the JIRAM instrument installed on Juno surveyed the surface of the moon. Interestingly, it was not originally designed for this purpose. JIRAM was created to study Jupiter’s atmosphere: the instrument can look 50 to 70 kilometers below the tops of its clouds. But, as it always happens in science, scientists have managed to adapt the instrument to solve additional problems.

While surveying the Southern Hemisphere of Io, JIRAM discovered a previously unknown hot spot in the Southern Hemisphere of the moon. Its size amazed scientists. The total area of the region is 100,000 km2. This is 2.5 times the area of the Sea of Azov. Its total power output is 80 trillion watts. That’s six times more than all of Earth’s power plants produce. The spot is such a powerful source of radiation that it saturated JIRAM’s infrared detector.

Surface changes at Io’s south pole in 2024, indicating powerful eruptions occurring there. Source: NASA/JPL-Caltech/SwRI/MSSS Image processing by Jason Perry

According to scientists, they speculate that Juno actually detected several nearby hotspots that were radiating at the same time. This suggests the presence of an extensive subsurface magma chamber system linking them. An eruption of this magnitude is likely to leave long-lived traces. It is currently the most powerful volcanic event ever recorded in the Solar System.

According to NASA

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