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A volcano on Jupiter's moon Io could erupt any day

Io seen by the Galileo spacecraft in 1999.
Io seen by the Galileo spacecraft in 1999. Photo: NASA/JPL/University of Arizona

Loki — a huge volcano on Jupiter's moon Io — is expected to erupt sometime this month.

Why it matters: Studying this volcano in deep space could help scientists learn more about how volcanoes on Earth formed in the planet's early history, according to planetary scientist Julie Rathbun.

What they found: Rathbun and her colleagues think that Loki actually erupts on a regular schedule, with an event lasting for about 100–200 days at a time.

  • Scientists on Earth are able to monitor these eruptions with telescopes that reveal Loki brightening and fading with each eruption.
  • Today, the volcano erupts once every 475 days or so, but in the 1990s, Loki brightened every 540 days.

But, but, but: Loki isn’t like a typical volcano you find on Earth. According to Rathbun, Loki is like a giant lake of lava on the moon’s surface.

  • "Since the surface of Io is so cold, the lava on top cools and turns solid. Eventually, this crust gets so heavy that it sinks and exposes more molten magma, this is when Loki is brightening and 'erupting,'" Rathbun told Axios via email.

The big picture: Studying Io's volcanic environment can also give scientists a better sense of what a volcano-dominated moon looks like, Rathbun said.

  • On Earth, water, plate tectonics, erosion and other large-scale processes shape the geology of our planet, but on Io, volcanism is the main driver, giving scientists a glimpse into a world very much unlike our own.