The Solar System


How did Phobos and Deimos become Martian moons?

The physical appearances of Phobos and Deimos are very similar to small asteroids. That, and the proximity of Mars to the asteroid main belt, suggests that they were indeed once asteroids whose orbits took them close to Mars. The orbital conditions were just right for Mars to capture them with its gravity, causing them to enter into stable orbits around Mars.


This is a web preview of the "The Handy Astronomy Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App