Conceptual Physics (12th Edition)

Published by Addison-Wesley
ISBN 10: 0321909100
ISBN 13: 978-0-32190-910-7

Chapter 9 - Think and Discuss: 93

Answer

If Earth and the moon had the same mass, indeed they would rotate around a common point exactly halfway between them. However, the Earth is so much more massive than the moon (by a factor of about 80) that the Earth and Moon rotate about a point, known as the barycenter of the Earth-moon system, that lies within the Earth. The barycenter is about 4700 km (about 3/4 of an Earth radius) from the Earth’s center.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.