Ocean of Magma Found Inside Moon of Jupiter

With over 400 active volcanoes, Jupiter’s moon Io is considered to be one of the most unique planets in the solar system. Newly analyzed research may hold the key to that moon's mysterious nature.

A group of scientists from UCLA, UC Santa Cruz and the University of Michigan have finished a new analysis of results from NASA’s Galileo spacecraft, which orbited Jupiter from 1995 to 2003. Their latest findings reveal the answer to Io’s supervolcanic activity: an ocean of molten magma that lurks as little as 100 feet below the surface.

Their results are being published in a study in the journal Science on May 13.

While the revelation of the ocean is a new discovery, the information collected from the original Galileo mission is actually close to nine years old. But the team didn’t start testing their hypothesis until 2008.

Why the delay? Science needed time to catch up with the findings.

“We saw a signal unexplained in our magnetic field data when the space craft flew by Io,” Dr. Krishan Khurana, a former co-investigator on Galileo's magnetometer team and a research geophysicist with UCLA's Institute of Geophysics and Planetary Physics, told FoxNews.com. “But we didn’t understand what the signal was until many years later, because our science wasn’t sophisticated enough at the time.”

The researchers were able to test their theory using electromagnetic induction, the same technique metal detectors use at airports. An ordinary metal detector generates an electromagnetic wave that bounces off reflective surfaces. The UCLA researchers did essentially the same thing -- but they used Jupiter to produce the reflection.

“Io as a result sees a variable field like an electromagnetic wave,” Dr. Khurana told FoxNews.com. "We were using Jupiter’s magnetic field as the electromagnetic wave, which is continually being reflected off a global subsurface conductor in Io. That conductor is the magma ocean.”

Recent research in mineral physics has found that certain kinds of rock become extremely conductive when melted, which led Khurana and his team to test the theory of a molten lava ocean. While the magma sea reveals why Io is in a constant state of volcanic eruption, it also explains why Io does not generate its on magnetic field.

“The magma ocean acts as a barrier to the heat transport to the interior of Io,” Dr. Khurana told FoxNews.com. “So it stops the heat from escaping from the core ... which shuts off the convection and shuts off the generation of a magnetic field.”

The discovery of Io’s ocean may not seem to affect our neck of the solar system, but the findings actually do reveal a bit more about our moon's past -- and even our Earth’s history.

According to the UCLA research team, both the moon and the Earth went through phases when each had a magma ocean, just after their formation. And it wasn’t until after the magma ocean froze that life was able to begin on our planet.

“The question for the Earth has been, when did the plate tectonics start?” Dr. Khurana said. “Plate tectonics are intimately interwoven with the evolution of life -- continents coming together and splitting apart. All of the geological activity on the Earth is created by plate tectonics. Well it turns out that if there is a magma ocean, it switches off plate tectonics.”

For now, Io remains a truly distinct planet. Dr. Khurana, comparing the surface of Io to a freshly baked pizza, noted that at 1/40 of Earth’s size, Io produces 40 to 100 times more lava each year than all of the volcanoes on Earth. And the research team’s discovery only adds to Io’s individuality.

“Io is the only planet that we know of in the solar system that has a magma ocean,” he said.