Io's Surface

As you can see in the picture above, the surface of Io is very unique. The dark spots you see are acutally volcanoes. There are over 400 active volcanoes on the surface of Io. However, the surface of Io is actually very cold considering it's covered in volcanoes. The surface temperature of Io is about -150 °C, and can be colder in some places. Io most likely has an iron core, and is about the same size as our own moon. It is also locked with Jupiter, so only one side of Io faces Jupiter throughout its orbit.


Looking at pictures of Io, there are no signs of impact craters anywhere on the surface. This is because of the several volcanoes that are scattered along Io's surface. When the errupt, the lava flows easy down into all dips, holes, or craters on the surface, and gives the surface a glassy appearance.When the volcanoes errupt, sulfur dioxide (SO2) is released among other gases. Since Io has a very thin atmosphere, most of the sulfur dioxide ionizes on its way out to space. Some of the gas even makes it to Jupiter. The ionized gas contributes to Io's torus, shown in the image below.

The torus is compsed of the sulfur dioxide's electrically charged particles which are stuck in Jupiter's magnetic field. Jupiter's magnetic field rotates with Jupiter, so a full ring is created in around ten hours. Some of these charged particles manage to make their way back to the surface of Io, and turns the surface red, orange, and white. The red and orange colors mainly come from sulfur ions, and the white colors come from sulfur dioxide.