A team of scientists from the American Space Agency has finally unlocked the secrets of the intense volcanic activity of Io, Jupiter's most turbulent natural satellite.
New secrets of Io revealed by the Juno space probe
Barely larger than the Moon (3,600 kilometers in diameter), Io is known to be home to some 400 volcanoeswhose gigantic plumes can be observed by the largest terrestrial telescopes. This spectacular geological activity was initially discovered in 1979, during the examination of a photo taken by the venerable Voyager 1.
Launched in 2011, the Juno space probe made two very close flybys of Io in 2023 and 2024, coming within 1,500 kilometers of its boiling surface. “ We knew that the data collected by Juno could help shed light on the internal dynamics of this tortured moon “, explains Scott Bolton of the Southwest Research Institute in San Antonio.
The hell moon makes a complete turn of Jupiter in 42.5 hours. The elliptical shape of its orbit implies significant variations in the distance separating it from the gas giant (422,000 kilometers on average) and, by extension, in the gravitational attraction that the latter exerts on it.
Essentially solid insides
While it was until now widely assumed that such features implied the presence of a global underground magma ocean, the new study, published in the journal Nature and based on Juno's measurements of Io's gravity, indicates a moon with essentially solid interiors, with volcanoes having their own magma chambers.
« The energy linked to these flexions [dues aux marées] constants literally melt parts of Io's insides », explains Bolton.
Shaking up our understanding of the Jovian moon, these results also have implications for that of Europa, which would show signs of liquid water, Enceladus, Saturn's natural satellite, and many worlds beyond the Solar System.
