Moons
Moons

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

2.4.1 A changing moonscape

Figure 49 An image of the Moon, roughly 200 km across the foreground, as seen from Japanese lunar orbiter SELENE.

Look at this image of the surface of the Moon. What do you notice about the number and size of craters across the image? Is there a difference between one part of the image and another? Why might this be?

This image shows the ancient lunar highland region to the right, with the younger, darker basaltic ‘mare’ (pronounced ‘MAH-ray’, Latin for ‘sea’) to the left. Because of the Latin origin of the word, the plural of mare is maria (pronounced ‘MAH-ria’). Early observers saw these dark smooth surfaces and guessed wrongly that they might be seas, hence the name.

The reason why there are so few craters on the left is that this area was flooded by volcanic lava after most of the impact craters were formed. You will study volcanic processes on the Moon and other moons next week.

MOONS_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 over 40 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