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Solar system
Mars' moon, Deimos

4.5 billion years, about the same age as Mars


Solar system, in orbit around Mars

Avg. distance from Mars

23,460 km (14,600 mi)


The non-spherical moon has the dimensions of 15 x 12.2 x 10.4 km (9.3 x 7.58 x 6.46 mi).


1.8 x 1015 kg

Orbital period around Mars

About 30.4 hours

Distinguishing features

Deimos is a nonspherical, potato-shaped moon with craters, but it has a noticeably smoother appearance than Phobos, the other Mars moon. Scientists debate whether the moons of Mars formed with the planet or are captured asteroids.

Mars' moon, Deimos

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"Fast Facts: Mars' moon, Deimos" is a table that lists the moon's age, location, average distance from Mars, diameter, orbital period around Mars, mass, and distinguishing features. A picture of Deimos is included.

Printer-friendly web page
Adaptable, at teacher's discretion
How to use in the classroom

Use this resource as:

A source of information. Read the table to find out about this object.

A large-number recognition and ordering activity. Have students review several Fast Fact moon tables, including this one. Have students read the tables to find each object's mass. Then ask them to arrange the objects according to their mass, from smallest to largest. Students also can arrange the objects according to their diameter.

A math activity. Use Newton's law of gravitation, the distance between Io and Jupiter, and the masses of the two objects to determine the gravitational force between them. (Recommended for grades 10-12)

An inquiry tool. Have students write down questions they would like answered about the image and the information in the Fast Facts table.

An engagement tool. Involve students in a discussion.

Related materials

Amazing Space resources by topic: Solar system

HubbleSite: Press releases on Moons