In December of 2024, a region on Jupiter’s moon Io blew its top. Several huge volcanoes were erupting at the same time – the most powerful volcanic event ever seen anywhere in the solar system. The outburst covered an area the size of West Virginia. During the hour that a spacecraft was watching, it produced enough energy to power the entire United States for days.

Io is by far the most active body in the solar system. It has hundreds of cones, lava pools, and other volcanic features. They’re powered by a constant tug-of-war between Jupiter and some of its other big moons. They pull and stretch Io’s interior, heating it up.

The 2024 eruptions were observed by Juno, a spacecraft that’s orbiting through the Jovian system. The region on Io had been quiet when Juno last looked at it, about two months earlier. So the eruptions must all have started at about the same time.

That suggests they were powered by the same source of magma below the surface. The magma must have traveled through a network of underground plumbing, allowing it to power several eruptions at once. So Io’s interior might be like a sponge, with lots of open spaces – that are sometimes filled with molten rock.

Jupiter appears just above our moon tonight. It looks like a brilliant star. Through binoculars, Io and Jupiter’s other big moons look like tiny stars quite close to the planet.

We’ll talk about one of Jupiter’s icy moons tomorrow.

Script by Damond Benningfield