Jupiter’s moon Io may have a hellish magma ocean beneath its surface

Jupiter’s moon Io may have a hellish magma ocean beneath its surface

Jupiter’s moon Io may have a hellish magma ocean beneath its surface

There are more than 200 moons in the solar system, but none are quite like Io, the third largest Jupiter’s 80 moons. Io is really, really volcanic. In fact, it is packed with so many hundreds of powerful active volcanoes that there must be something unusual beneath its crust.

That something could be a thick layer of molten rock across the moon — or a “subterranean ocean of magma,” according to a new study published in Planetary Science Journal Nov. 16 by Yoshinori Miyazaki and David Stevenson, planetary scientists at the California Institute of Technology.

That possible super-hot sea of ​​molten rock – which is unique in the Solar System – could hide secrets, strange mechanisms for moon and planet formation, and even recipes for exotic alien life. Only further examination of the 2,200-mile-diameter moon will tell.

Miyazaki and Stevenson aren’t the first scientists to take a good guess at what lies beneath Io’s potentially 20-mile-thick rocky crust. It has been the subject of heated debate for years. But their new peer-reviewed study of the moon’s mantle may be the most thorough yet.

Volcanic explosion on Io, Jupiter’s third largest moon, captured by NASA’s New Horizons spacecraft.

NASA/JPL/University of Arizona

To peer beneath Io’s surface, Miyazaki and Stevenson revisited a wealth of data from NASA Galileo probewhich orbited Jupiter for eight years beginning in 1995. Initial analysis of the probe’s magnetic data led to a loose consensus that Io’s mantle—the layer beneath the moon’s crust—includes a 30-mile-thick upper layer that should be “molten or partially molten,” according to NASA.

Compare this to Earth’s own mantle, as well as the mantle of every other planetary body in the Solar System, which are mostly solid and composed mostly of ice or superheated rock. In general, planetary scientists reading Galileo’s data assumed that Io either had a subsurface magma ocean or some kind of spongy, rocky, magma-soaked outer shell.

A fresh look at the data led Miyazaki and Stevenson to the conclusion that it was a molten sea. They based their conclusion on estimates of mantle temperature through analysis of Io’s volcanoes, which can spew magma hundreds of miles into the moon’s sulfur dioxide atmosphere. The top of the mantle could be as hot as 2,800 degrees Fahrenheit.

That’s hot. But not hot enough to withstand the spongy interior. The analysis is complicated, but it boils down to this: Like a pot of gravy on the stove, Io would need a lot of heat to stay consistently spongy in its upper mantle. Without enough heat, the sauce—er, spongy rock—would separate: rock at the bottom, magma at the top.

Miyazaki and Stevenson ran the numbers, calculating the heat from Io’s core as well as the effects of its strange, highly elliptical orbit, which splashes the mantle, spreading heat around and preventing Io from cooling permanently.

They concluded that the sauce would separate. “The amount of internal heating is insufficient to maintain a high degree of melting,” they wrote. Hence what they believe could be the highest magma ocean.

Luckily, we’ll find out more soon. NASA Juno probe, which arrived around Jupiter in 2016, should take readings on Io in 2023 and 2024 – specifically measuring the “love number,” a gauge of the planet’s rigidity, or lack thereof. “If a large amount of love is found, we can say with more certainty that a magma ocean exists beneath Io’s surface,” Miyazaki told the Daily Beast.

We already knew Io was weird. It is possible that it is even weirder— and that weirdness could have implications in the space sciences. “I don’t think it changes our understanding of planet formation very much, but it does change the way we look at the internal structure and thermal evolution of tidally heated bodies like Io,” David Grinspoon, a senior scientist at the Arizona-based Institute of Planetary Sciences, said in a statement. he told the Daily Beast.

Io and Europa, Jupiter’s two largest moons, imaged by NASA’s Juno spacecraft.

NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko

Astrobiologists lurk in the shadows of academia. Experts on how and where life might evolve in the universe. If there is alien life out there that looks like life on Earth, we should expect to find it—or evidence of its extinction—on planets and moons that have or had Earth-like environments. Mars. Venus. He summoned Saturn’s moon Enceladus.

But volcanoes, with their extreme energy transfer, are widely regarded as key components of living ecosystems. So planets and moons with lots of volcanoes are great places to look for extraterrestrial life. In theory, this should include Io.

However, Io could too much volcanoes. So if life is developing there, it’s probably very strange life really likes the heat. “Lava tubes could create favorable conditions for microbes,” Miyazaki said.

The question for astrobiologists is whether a magma ocean would create more or fewer lava tubes than magma sponges. “I don’t have an explicit answer,” Miyazaki said. “But it’s interesting to think about those implications.”

Dirk Schulze-Makuch, an astrobiologist at the Technical University of Berlin, has long advocated a thorough search for life on Io. A magma ocean would only spoil that search if it was really close to the surface. A nice thick crust should insulate the outermost parts of the planet from the heat and preserve the potential for evolution. “There seems to be a lot of crust,” Schulze-Makuch told the Daily Beast.

If anything, the possibility of a magma ocean on Io only underscores how interesting and exciting the moon is — and why it should be a prime target for future space probes, Schulze-Makuch said. “Io is a unique kind of moon, very dynamic, and we shouldn’t completely dismiss it.”

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