Mars’s 2 Moons: Phobos And Deimos [Easy Guide]

Mars's 2 Moons: Phobos And Deimos [Easy Guide]

Just as Earth has one moon, Mars actually has two such moons that are part of its distinct properties, having several influences on what Mars exhibits as a planet. To learn more about both the Mars moons, you can go through the following sections.

Mars’s 2 Moons: Short Summary

Mars is the planet that follows Earth when it comes to its location from the Sun. It has two moons, named Phobos and Deimos. Both of these are highly irregular in their shape, unlike the spherical appearance of Earth’s moon.

These moons were discovered in the year 1877 by Asaph Hall, an astronomer. They were later observed and captured in images in an even clearer manner due to advancements in telescopic technologies.

These moons are smaller than Earth’s moon, with Phobos being both larger and closer to Mars as compared to Deimos.

Here’s a short YouTube video that briefly explains details about these two moons.


The Two Moons of Mars

Phobos and Deimos are the two moons of Mars, each of which has its own distinct characteristics and influences on Mars. Both also differ from each other on the basis of their size and distance from the planet.

You can go through each of them in further detail below.


Phobos is the moon that tends to be in a closer orbit to Mars. It measures 17 x 14 x 11 miles or 27 x 22 x 18 kilometers in diameter and takes around 7.5 hours to complete its orbit around Mars.

It has a crater on its surface that spans six miles and has plenty of dust and rocks as part of it. Due to meteorites, the surface of this moon contains these craters.

The temperature ranges from 25℉ to -170℉. Phobos is expected to crash into the planet in the next few million years or scatter itself into a ring around the planet.


Deimos measures 9 x 7 x 6.8 miles or 15 x 12 x 11 kilometers in size. It also has an irregular shape but is located much further away from the surface than Phobos. The surface is further relatively smooth, although there are still several small craters.

Deimos has an extremely small gravitational force. Over the next 50-100 million years, it is likely that this moon might remove itself from the orbit of Mars.

Deimos takes over 30 hours to complete its orbit around Mars.


Frequently Asked Questions

Are The Two Moons On Mars Asteroids?

Yes, the moons are likely to be captured asteroids.

Are The Moons On Mars The Smallest?

As compared to other moons in the solar system, Phobos and Deimos are some of the smallest.

Conclusion and Summary

Phobos and Deimos, the two moons of Mars, are extremely small in size and have irregular potato-like shapes. Phobos is slightly larger in size as compared to Deimos and is also closer in orbit.

In the next 50 to 100 million years, it is possible for the two moons to undergo changes in their location and no longer be the moons of Mars.

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