Moons of our Solar System
Moons of our Solar System

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Moons of our Solar System

3 What makes a moon?

Described image
Figure 35 Planets, moons and asteroids to scale

With moons so widely distributed in the Solar System, it’s natural to ask what they are. There are a large number, with the majority in the outer Solar System, orbiting the giant planets Jupiter, Saturn, Uranus and Neptune. It is not believed that a moon can have a smaller moon in a stable orbit around it, and this has never been observed. What makes a moon? There are many sizes and compositions and there doesn’t seem to be a single explanation that holds for all.

Even our own Moon’s origin remains a topic of research.

MOONS_BOC_1

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, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 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 prospectus371