If there were a world in our planetary system that could be called “Hell,” this would be its moon ForIo.

It is the celestial body with the most active volcanoes in our solar system, a fact that is impressive in itself and yet opens up prospects for the deep future, as the Earth it was some millions of years ago, a world full of volcanoes, which evolved into today’s wonder and the explosion of life that followed during that time.

NASA’s Juno reveals amazing images and data from its investigation of Jupiter’s physical moon. Everything we have learned recently is captured in an impressive video animation by NASA. A video that takes us to impressive worlds, different from our Earth, yet so attractive and wonderful.

Watch the video animation:

A major and equally important finding of NASA scientists from Juno’s investigation of Io is that the volcanoes are fed by magma from their own chamber and not from a vast ocean of magma that lies solidly beneath the moon’s crust. After 44 years of study, scientists are now able to come up with real solutions to the prospect of our solar system’s ‘hell’.

About the size of the Moon, the Oh is known as the most volcanically active body in our solar system. The moon is home to about 400 volcanoes, which spew lava in seemingly continuous eruptions that help coat its surface.

Io was discovered in 1610 by Galileo

Although the moon was discovered by Galileo on January 8, 1610, the volcanic activity was not discovered until 1979, when the scientist Linda Morabito of NASA’s Jet Propulsion Laboratory in Southern California first spotted a volcanic plume in an image sent back by Voyager 1.

“Since Morabito’s discovery, planetary scientists have wondered how volcanoes were fueled by lava below the surface,” said Scott Bolton, principal investigator of the Juno mission at the Southwest Research Institute in San Antonio. “Was there a shallow ocean of white-hot magma feeding the volcanoes, or was their source more localized? We knew that the data from Juno’s two very close flybys could give us some insight into how this tortured moon really worked.”

The “tidal bend” phenomenon

Juno made extremely close flybys of Io in December 2023 and February 2024, coming within about 1,500 kilometers of its surface. During the approaches, Juno communicated with NASA’s Deep Space Network, sending high-precision Doppler data, which was used to measure the moon’s gravity. The data sent gave surprising results, as a phenomenon called “tidal bending” was observed.

Io is extremely close to the gas giant Jupiter, and its elliptical orbit takes it around the planet once every 42.5 hours. As the distance varies, so does Jupiter’s gravitational pull, which leads to the relentless compression of the moon. The result: an extreme case of tidal bending — friction from tidal forces that generates internal heat.

“This constant bending creates enormous energy, which literally melts parts of the moon’s interior,” said Bolton. “If Io had a global magma ocean, we knew that its tidal deformation signature would be much larger than a more rigid, mostly solid interior. So, depending on the results from Juno’s detection of its gravitational field, we could tell if a global magma ocean was hiding beneath its surface or if it was something else.”

The Juno team compared data Doppler from its two flybys with observations from the agency’s previous missions to the Jovian system and from ground-based telescopes. They found tidal deformation consistent with Io not having a shallow global magma ocean.

“Juno’s discovery that tidal forces do not always create global magma oceans prompts us to rethink what we know about the interior of Jupiter’s moons,” said lead author Ryan Park, one of the Juno mission investigators and supervisor of Solar System Dynamics Group at JPL. “It has implications for our understanding of other moons, such as Enceladus and Europa, and even exoplanets and super-Earths. Our new findings provide an opportunity to rethink what we know about the formation and evolution of planets.”