lava lake where mountains become smooth as glass

• The Juno mission team reconstructed the volcanic lake Loki Patera thanks to images from the probe.

• The Galilean moon Io is the most volcanically active body in the Solar System.

If we had to choose which worlds in the solar system have the best color palette, Io would be among the finalists. Jupiter’s bright moon is covered in vibrant yellow, red, white and black colors. And thanks to NASA’s Juno probe, we can see them closer.

Flyby of Juno. The Juno space probe was launched in 2016 aboard a United Launch Alliance Atlas V rocket.

Eight years later, in December 2023 and February 2024, Juno accomplished an unprecedented technical and scientific feat: two very close flybys of Io, during which it was able to photograph the moon’s northernmost latitudes, as close as 1,500 kilometers from its surface.

An island in a huge lava lake. These images allowed the NASA team to computer reconstruct one of Io’s most notable features: Loki Pateru, a lava lake about 200 kilometers in diameter with a crystallized mountain at the center, as if it were a collection of islands.

Scientists have been observing this lake, located on magma deposits beneath Io’s surface, for decades. The lava cooled in the center, forming a mountain. The reflection captured by Juno’s instruments suggests that some parts of this mountain are as smooth as obsidian glass, which is produced volcanically on Earth.

Most strikingly, the mountain is surrounded by molten magma, like rocky islands in a lake of hot lava, as Juno’s principal investigator Scott Bolton revealed during the European Geophysical Union General Assembly in Vienna last week.

The most volcanically active body in the solar system. Io is one of the four Galilean moons of Jupiter discovered by Galileo Galilei in 1610. It is characterized by extreme volcanism. Its surface is dotted with hundreds of volcanoes, some of which emit plumes of sulfur up to 500 kilometers high.

This volcanic activity is the result of Jupiter’s enormous tidal forces. Io’s elliptical orbit and the gravitational influence of Jupiter and other Galilean moons cause frictional heating within it, eventually releasing material in energetic eruptions.

As if that weren’t enough, we know that Io experiences thunderstorms and lightning, likely caused by eruptions spewing material high into its thin atmosphere.

Image | POT

In Hatak | Juno has just given us an image we’ve never seen before: a river of lava on a moon of Jupiter.