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

2.3 Comparing craters

How do craters on the Moon form?

To many scientists over the last few centuries, the obvious answer was to look to the Earth for similar features. People already knew about the craters found on volcanoes. Such craters form when magma drains downwards after an eruption, leaving a circular depression (sometimes known as a ‘caldera’) at the surface, or when a volume of rock is ejected by an explosive eruption.

The apparent similarities between volcanic craters and images of lunar craters seemed to answer the question of how the Moon’s craters were formed.

Described image
Figure 23 Aerial photograph of a volcanic caldera on Kilauea, Hawaii
Described image
Figure 24 Aristarchus crater on the Moon, as photographed by Lunar Orbiter 5 in 1967

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