Epic Jupiter’s hellish moon flyby reveals a lava lake that could swallow cities

No world is wilder than Jupiter’s moon Io.

It has more volcanic activity than any other body in the solar system, and its sphere is only slightly larger than Earth’s cold, dusty moon. Its surface is dotted with volcanoes, about 400 of which are active at any given time.

Io is an absolutely jaw-dropping place, and we just got a front-row seat to some of its strange, untameable landscapes.

When NASA’s Juno spacecraft made two close flybys of Mars moon In December 2023 and February 2024, it captured some of Io’s fire and fury by observing regions we’d never seen before – northern latitudes.

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“Io is full of volcanoes, and we captured some of them in action,” said Scott Bolton, a space physicist at Southwest Research Institute (SwRI) and principal investigator of the Juno probe. .

“We also got some fantastic close-ups and other data of a 200-kilometer-long (127-mile-long) lava lake called Loki Patera. Stunning detail shows these crazy islands embedded on the edge of a potential lava lake with thermal lava.

“Specular reflections from the lake water recorded by our instruments indicate that parts of Io’s surface are as smooth as glass, reminiscent of obsidian glass formed by volcanoes on Earth.”

Io may be small in relative terms, but its impact is huge due to its complex relationship with Jupiter.

As the moon follows Jupiter’s elliptical orbit, changing gravitational stress causes Io’s interior to heat up. The other two Galilean moons Europa and Ganymede also exert gravitational pull, further putting pressure on Io’s interior.

All this heat is ejected from Io in the form of rampant volcanic activity. It spews volcanic gases that are released from Io’s weak gravity and pulled into the vast ring of plasma that surrounds Jupiter.

This plasma is pulled along the lines of Jupiter’s magnetic field and accelerated to its poles, where it fuels the most powerful permanent, powerful ultraviolet auroras in the solar system.

And this isn’t a short-term thing either. New analysis of two sulfur isotopes in Io’s thin atmosphere shows that the heavier isotope is present in disproportionate amounts. The lighter one rises to the top of the atmosphere, where it is more likely to be stripped off and join the ring of plasma surrounding Jupiter.

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The ratio of the two isotopes shows that Io has been undergoing this stripping process over its 4.5 billion year life. Jupiter is thought to be the first planet to form in the solar system, so its invisible auroras may have always illuminated space.

Juno’s mission is ongoing and will include more flybys of Io, Jupiter (of course) and other Galilean moons.

However, Io holds a very special place in our hearts and imaginations, a world that represents some of the fascinating extremes of the universe, right here in the solar system.

Imagine what it would be like if we had the ability to go there.

The Juno team presented their latest findings at the European Geosciences Union Congress in Vienna.