Nasa’s Juno spacecraft just flew incredibly close to Io, one of Jupiter’s most intense and fascinating moons. And what did it catch? A glowing lava lake so smooth it actually reflects sunlight, like a mirror… and all of that, placed on a volcanic moon that’s constantly erupting. That’s Loki Patera, and thanks to Juno, we now have the clearest view of it we’ve ever seen.
Juno made two ultra-close flybys of Io—one in December 2023 and another in February 2024—flying just 930 miles above the surface. The images and data it sent back are blowing scientists’ minds. Scott Bolton, Juno’s lead scientist, shared the findings this spring at the European Geophysical Union, and to be honest, they sound unreal.
Io isn’t like Europa, Ganymede, or Callisto, its more chill moon siblings. This place is a volcanic hellscape. Juno captured so much more than just glowing rivers of magma: actual plumes of sulfur, clouds of sulfur dioxide, and a surface that reflects light like volcanic obsidian. Yes, obsidian. You know, the black glass stuff that forms from cooling lava on Earth? Io is covered in that, but on a way more massive, alien scale.
Io’s poles turned out to be colder than its middle latitudes. Somehow, even on a moon full of volcanoes, there are still icy zones. This moon doesn’t play by the rules.
Loki Patera: a lava lake that literally glows
Let’s talk about Loki Patera, because it’s honestly wild. It’s not just big—it’s massive. Over 200 kilometers wide. From space, it looks like a huge dark oval. But what Juno saw up close is way cooler: the surface of the lake is so still and shiny, it reflects sunlight back like a sheet of glass.
That shine tells scientists it’s probably formed from rapidly cooling magma, turning into smooth volcanic obsidian. And there are actual “islands” inside the lake. Floating. In lava. Around it, there’s glowing lava at the edges and plumes of sulfur dioxide rising up into Io’s thin atmosphere. It’s basically an alien volcano paradise. Or nightmare. Depends how you feel about standing near rivers of lava.
Meanwhile, Jupiter’s got some strange storms brewing
While Juno was capturing Io’s chaos, it also turned its instruments back toward Jupiter, and what it’s finding up there is just as weird. Especially around the north pole.
It shows up just fine in regular and infrared images, but in the microwave data, it basically fades away. That’s a pretty strong hint that something unusual is going on under the surface, maybe this storm is built differently from the others, or made of something we don’t fully understand yet.
Each orbit, Juno collects more data, and scientists are slowly building a 3D view of these storms. And the more they see? The more questions they have.
Still a questions on the horizon: How did the Solar System form?
One of Juno’s big missions is to figure out how much water is hiding in Jupiter’s atmosphere. It’s not water like oceans or lakes—it’s tiny hydrogen and oxygen molecules buried deep inside Jupiter’s thick atmosphere. figuring out how much of it is there gives scientists clues about how jupiter formed, and even how the whole solar system started coming together billions of years ago.
Back in the ‘90s, NASA’s Galileo probe dropped into Jupiter and barely found any water, which didn’t make sense. But now we know why. Thanks to Juno, scientists discovered Galileo just landed in a weirdly dry spot. Juno’s data shows that near the equator, Jupiter’s water content is actually three to four times the solar average.
Jupiter’s core might be way drier than expected and no one really knows why yet. Maybe future Juno flybys around the polar regions will help clear things up.