IO is the 3rd largest of the 4 Galilean moons discovered by their namesake, Galileo Galilei, who was a philosopher, astronomer, mathematic, and physicist, (info in sources). IO is a chilly place with a average temperature of -202 degrees Fahrenheit due to the atmosphere not being thick enough to hold heat, despite the fact that it is a volcanic moon with vast rivers of lava with high temperatures around the lava flows estimated at 3000 degrees Fahrenheit, which is hotter than almost every lava flow on earth.
IO has the appearance of a hellscape with a dark gas filled thin atmosphere. Hundreds of active volcanoes spewing thick magma kilometers up into the sky, often being able to be seen from the moons orbit with ash and magma floating off of the moons horizon.
The scientific community has suggested that IO may have a giant ocean of magma that the moons surface floats on. Planetary scientist David Stevenson of Caltech says, on December 15 at the American Geophysical Union’s fall meeting, “Though the exact size of the proposed molten sea remains uncertain, it would need to be relatively large. The magma ocean could be, say, 100 kilometers thick.”
But the scientists are unsure if it is a pure giant ocean of lava, or if there are only pockets of magma like a giant lava filled stone sponge. The scientist have concluded that IO has a lava ocean, “The final conclusion is [that] Io has a magma ocean.” But there are other possibilities. “A lot of information is consistent with a large, global conductive layer that could be a magma ocean,” Howell says. “But I wouldn’t say there’s consensus on how to interpret that data.”
Another thought is that a giant ball of pure metal lurks in the depths of IO’s great magma ocean. This core could have numerous precious metals used for many uses. Missions to IO and continuing missions like NASA’s Juno mission, as well as 2 missions, NASA’s Europa Clipper and the European Space Agency’s JUICE mission (yes really juice) will explore the strange planetary volcano that is IO.