|Galilieo spacecraft shows Jupiter's moon Io. (NASA photo)|
That goes a long way toward explaining why Io is the most volcanic body in the known solar system, producing about 100 times more lava every year than all the volcanoes on Earth.
Researchers determined the existence of the massive magma ocean when the Galilieo spacecraft detected strange patterns in magnetic field data from the moon.
“It turns out Io was continually giving off a ‘sounding signal’ in Jupiter’s rotating magnetic field that matched what would be expected from molten or partially molten rocks deep beneath the surface,” the UCLA’s Krishan Khurana, lead author of the study, said in a NASA statement.
Rock samples studied by Khurana’s team showed molten magma is present just under Io’s crush. Unlike on Earth, it’s not likely to just be gathered in pockets near fault lines.
Instead, scientists describe a “global magma ocean” miles below the moon’s surface.
That might have also been the case on Earth and the Moon billions of years ago, according to NASA:
While Earth’s volcanoes occur in localized hotspots like the “Ring of Fire” around the Pacific Ocean, Io’s volcanoes are distributed all over its surface. A global magma ocean about 20 to 30 miles (30 to 50 kilometers) beneath Io’s crust helps explain the moon’s activity.
“It has been suggested that both the Earth and its moon may have had similar magma oceans billions of years ago at the time of their formation, but they have long since cooled,” said Torrence Johnson, a former Galileo project scientist based at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. He was not directly involved in the study. “Io’s volcanism informs us how volcanoes work and provides a window in time to styles of volcanic activity that may have occurred on the Earth and moon during their earliest history.”