The Names All Of Mars' Moons And Some Amazing Facts About Them

Outdoor & NatureLearn more
Outdoor & NatureLearn more

Share this article

The universe is a very complex place, and there are so many things that have been discovered, yet there are more to be found.

NASA, the largest organization working to solve these mysteries, is the most authentic source of astronomical information. Talking about the universe, we will discuss the moons or two natural satellites of the fourth planet in the Solar System - Mars.

Mars, well-known as the red planet, is the second smallest planet after Mercury. Mars is named after the Roman god of war. The two Mars moons named Phobos and Deimos orbit the planet. Next to Earth, this planet has always been fascinating to the scientists who have been working on the idea of building human settlements on this planet.

Till now, they have been successful in discovering traces of water ice that could lay the foundation of human settlements on Mars. But there are no clear indications as to when a human will set foot on Mars. Here we will discuss the moons - Phobos and Deimos - and some amazing facts associated with them.

Mars has two moons, Phobos and Deimos, which orbit around it, while the Earth has only the Moon as its natural satellite; both the planets revolve around the Sun.

The Earth's orbit around the Sun takes approximately 365 days, while the Earth’s Moon takes a total of 28 days to complete one revolution around the planet. Similarly, Mars's Phobos and Deimos orbit around it, but their speeds, size, distance, and phases are different.

Here we will be looking at such information regarding these two Mars moons, along with some amazing fun facts that will further pique your interest in astronomy.


Phobos orbits around Mars at a faster pace and is the larger moon of the two. Phobos, a moon of Mars, was named after Phobos, the Greek god.

This Greek god is the twin brother of Deimos and the son of Ares and Aphrodite, Mars and Venus, respectively. This specific god in Greek mythology is considered the personification of panic and fear, out of which the word 'phobia' is born.

Phobos, along with Deimos, was discovered by Asaph Hall, an American astronomer, in 1877 and is the closest satellite of the planet Mars. The dimensions of the moon are 16.8 x 13.7 x 11.2 mi (27 x 22 x 18 km), while the surface is irregular with a mean radius of 7 mi (11.26 km). This celestial body is distinctive and small and revolves around Mars with a speed of 1.3 mps (2.1 kps).

This larger moon of Mars is considered to be doomed as the distance between Mars and Phobos is decreasing at a rate of 6 ft (1.8 m) every 100 years due to decreasing orbital radius of the moon. This will either result in a collision between the two or it breaking into a ring around the red planet. This will take approximately 500 million years.

If we consider the unique features of this Martian moon, then Stickney, a crater of 6 mi (9.6 km), is the reason behind the streak pattern on the surface of this giant Mars moon.

Phobos lacks an atmosphere and is a cold moon with a temperature of 24.8 F (-4 C) on the side exposed to the sun and a temperature of -274 F (-170 C) on the other side. Also, this is the least reflective body in the Solar System and is not very absorbent towards heat due to the layer of fine dust on its surface.


The naming of this moon of Mars has been discussed earlier, but the Greek god Deimos represents dread and terror. The discovery of this celestial body was made in the same year as Phobos by the same astronomer Asaph Hall.

Martian moon Deimos is the second moon from mars and is irregular in shape. The dimension of this moon of Mars is 9.3 x 7.6 x 6.8 mi (15 x 12.2 x 11 km) with a surface area of 191 sq mi (495.15 sq km). The speed of the revolution on its axis is 0.85 mps (1.35 kps), and it takes approximately 30.3 hours to complete one revolution around Mars.

This moon is further from the Martial surface and is also the smaller one among the two, with only a mean diameter of 7.7 mi (12.4 km).

If this moon is viewed from the surface of Mars, then it is nothing but the size of a star. Still, on the full moon, this celestial body shines very brightly even to the level of comparison between Venus and itself, albeit that Venus is among the brightest objects in this solar system.

The temperature of this body is about 24.8 F (-4 C) on the side facing the Sun. In comparison, the darker side temperature might rise to an average of -169.6 F (-112 C).

While the Martian moon Phobos is moving closer, Deimos is moving further from it and might escape into space once the gravitational pull of Mars becomes lesser and ineffective to hold it into its orbit.


The distance of the Martian moons is what makes them attractive. While one is coming closer to the planet with each passing century, the other is moving farther away.

While Phobos is all set to crash into the red planet, the other is ready to escape into space without the binding gravity of its planet. The present distance between Mars and Phobos is 3,700 mi (6,000 km), while between Deimos and Mars, it is 14,573 mi (23,460 km). The first takes 0.318 Martian days for one revolution; the latter takes 1.26 Mars days to complete one revolution.

While the present distance between the planet and its moons is mentioned, this distance will increase every century for Deimos and decrease for Phobos. Finally, there will be no natural satellite left for this red planet.

Deimos takes just over a Martian day to complete its orbit around Mars.

Amazing Facts About Mars' Moons

A favorite of the astronomers, Mars, continues to be explored by many a scientist with the invention of advanced technology.

It is estimated that Jupiter's gravity would have nudged these two objects from the asteroid belt into an orbit around Mars.

As much as scientists study the planet, the moons are considered super weird. Not because they are small or shaped irregularly (like potatoes) but because they are far from anything like the moons of Saturn, or Jupiter, or even the Earth’s Moon.

Here, we will be reading some more fun and enthralling facts about these two small moons - the little companions of Mars.

They have never been stepped upon yet. Russia and the USA's NASA both tried but in vain during the ongoing great space war. The third one is in Japan, which has set a goal to bring some Phobos’ stones back home for inspection.

The information we have to date about these two celestial bodies is all due to scientists’ observations. If the Japanese mission gets successful, we might be able to solve some more mysteries of these two.

The hope for Japanese advancement is high as this may put an end to the theories about the origin of these Mars moons, Phobos and Deimos, and will help discover many more mysteries.

These Martian moons have been fascinating due to their origin, behaviors, and nature. "They’re super weird, confusing, and interesting", says Abigail Fraeman, a scientist studying planetary motions and developments of Mars.

Phobos orbits Mars faster than Mars completes its rotation around the axis.

As per NASA, the origin of these moons is confusing as they look like asteroids, basically foreigners to the red planet, but their behaviors are like the byproduct of Mars.

One of the most interesting facts about them is their distance, changing every century.

Many theories and observations regarding their origin and demise exist, but accepting any one of them is presently tricky.

Some NASA scientists believe that these two should not even be circling Mars in their tiny little circular orbits.

Asaph Hall discovered both the moons of Mars.

Astronomer Gerard Kuiper was the first to locate the asteroid belt after Neptune. Phobos and Deimos have captured asteroids due to the gravitational pull of Mars. According to NASA, between Mars and Jupiter, there is a lot of space debris and rock, including the asteroids. The rock, debris, and asteroids are leftover from the Solar System’s formation.

It may be difficult to see the Mars moons with naked eyes in the night sky. The small moons of Mars are smaller than the Earth’s Moon. 

Some craters on the Mars moons are Hadley crater, Halba crater, Haldane crater, Hale crater, Herculaneum crater, Honda crater, Hashir crater, and others.


Written By

Kidadl Team

The Kidadl Team is made up of people from different walks of life, from different families and backgrounds, each with unique experiences and nuggets of wisdom to share with you. From lino cutting to surfing to children’s mental health, their hobbies and interests range far and wide. They are passionate about turning your everyday moments into memories and bringing you inspiring ideas to have fun with your family.

Was this article helpful?

Get The Kidadl Newsletter
1,000's of inspirational ideas direct to your inbox for things to do with your kids.

By joining Kidadl you agree to Kidadl’s Terms of Use and Privacy Policy and consent to receiving marketing communications from Kidadl.