Juno probe uncovers the fiery secret of Jupiter's moon Io
NASA reveals new information. Thanks to the Juno probe mission, a mystery about Jupiter's moon Io that lasted over 40 years has been solved. It is now known why Io is the most volcanically active body in the Solar System.
9:46 AM EST, December 18, 2024
Io is the third-largest natural satellite of Jupiter. Its thin atmosphere consists mainly of sulfur dioxide, and its characteristic yellow, orange, and red colors result from being covered in sulfur. Scientists have long been fascinated by it, primarily because it resembles our Moon in size and is known as the most volcanically active body in the Solar System, with approximately 400 volcanoes that eject lava and gases in nearly constant eruptions.
It's not a magma ocean causing the unusual activity
NASA scientists have been studying Io for nearly 44 years. They previously believed that a magma ocean beneath Io's surface was responsible, but now it turns out that's not the case.
While Io was discovered by Galileo in 1610, its volcanic activity was identified nearly 400 years later. The first traces of volcanic plumes on Io were detected in 1979 by NASA scientist Linda Morabito, who was analyzing images from the Voyager 1 probe. Since then, scientists, including Scott Bolton from the Southwest Research Institute, have been questioning the mechanisms fueling these volcanoes from within. In December 2023 and February 2024, the Juno probe conducted close flybys over Io, getting as close as approximately 930 miles.
As scientists explain, Io is extremely close to Jupiter, and its low orbit means it circles the gas giant every 42.5 hours. Furthermore, its orbit is elliptical, so as the distance from the planet changes, the gravitational force acting on the moon also changes, causing it to be constantly compressed. The result is extreme tidal deformations due to friction caused by tidal forces that generate internal heat.
A groundbreaking discovery about the interior of Jupiter's moon
NASA scientists determined that Io's interior is most likely mostly solid, and each volcano on Io has its own chamber of liquid magma, not connected to others. The results obtained from these flybys, earlier missions, and ground-based telescope measurements indicated the absence of a magma ocean beneath Io's surface.
- Juno’s discovery that tidal forces do not always create global magma oceans does more than prompt us to rethink what we know about Io’s interior, emphasizes the lead author of the publication, Ryan Park. As he adds, it also has implications for our understanding of other moons, such as Enceladus and Europa, as well as exoplanets, including super-Earths.
- Our new findings provide an opportunity to rethink what we know about planetary formation and evolution [of planets], explains the lead author of the publication.
Researchers are hopeful for more discoveries from the Jupiter system that may emerge soon. On November 24th, the probe completed its 66th flyby over Jupiter's cloud tops, and on December 27th, a particularly close approach to the planet will occur. When Juno's orbit is closest to its center, it will be approximately 2,200 miles above the cloud tops.