Jupiter's lunar volcano could erupt this month

Loki is primed to blow in mid-September, a scientist predicts.

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The volcano Loki on Jupiter's moon Io. Eruptive activity originated in the lower left area of the dark linear feature in the center. The U-shaped area is the "lava lake."


At any moment, a surge of molten lava is expected to erupt from a 126-mile-wide volcano named Loki onto the surface of Jupiter's innermost moon, Io. And if it does, us earthlings' ground-based telescopes will be able to marvel as the celestial body brightens and its toroidal clouds of plasma encircle Jupiter. Or that's what a leading Io scientist expects, anyway.

Based on more than 20 years of lunar observations, Julie Rathbun, senior scientist at Planetary Science Institute, says Loki's brightenings signal an on-schedule eruption that could be predicted approximately every 475 days. Rathbun presented her studies in a poster Tuesday at the European Planetary Science Congress' 2019 Joint Meeting in Geneva.

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"Loki is the largest and most powerful volcano on Io, so bright in the infrared that we can detect it using telescopes on the Earth," Rathbun said in a release from the Europlanet Society. "If this behavior remains the same, Loki should erupt in September 2019, around the same time as the EPSC-DPS Joint Meeting 2019. We correctly predicted that the last eruption would occur in May of 2018."

In January, cameras aboard NASA's Juno spacecraft caught an extraordinary glimpse of a massive volcanic plume as it shot material off Io's surface, in what the space agency calls the "most volcanically active spot in the solar system." 

Though Loki's enormous size has a stabilizing effect on its cycles, making it more predictable than many volcanoes, Rathbun remains cautious. 

"You have to be careful because Loki is named after a trickster god and the volcano has not been known to behave itself," she said. "In the early 2000s, once the 540-day pattern was detected, Loki's behavior changed and did not exhibit periodic behavior again until about 2013."