Moons of our Solar System
Moons of our Solar System

This free course is available to start right now. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation.

Free course

Moons of our Solar System

1.4 A closer look at volcanism on Io

Io has hundreds of centres of volcanism on its surface, caused by the tidal heating from Jupiter creating a huge tidal bulge at the surface. Eruption temperatures have been measured up to 1400 °C. It’s likely that the material erupted would be similar in composition to an Earth basalt. The huge Tvashtar plume that you saw in the previous video was most likely composed of pyroclastic material, sulfur and sulfur dioxide. With no atmosphere to hinder the plume, it created a huge umbrella as gravity pulled the material back to the surface. Many of the volatiles erupted escape into space, however, and are thought to land on other nearby moons such as Europa. The lack of impact craters on Io’s surface demonstrates the young age of the surface as new craters are quickly flooded by lava or buried by fall-out from plumes.

In Figure 11 the 200 km circular feature near the upper right is because we are looking down through a persistent eruption plume at Prometheus volcano. The Galileo image shows more detail, but many genuine changes have occurred on the surface, notably the dark lava flow that was erupted from the volcano between these two dates.

Described image
Figure 11 The same 600-km wide region of Io seen in 1979 by Voyager (left) and seen in 1997 by the Galileo spacecraft (right).

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to university level study, find out more about the types of qualifications we offer, including our entry level Access courses and Certificates.

Not ready for University study then browse over 900 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus