The Moons of Mars

The Moons of Mars

tl;dr Mars is the fourth planet from the Sun, it’s red and there may or may not be Martians there. Most importantly, Mars has two moons; Phobos and Deimos. These two moons are named after scary characters from Greek Mythology; Phobos known for panic and fear, Deimos known for terror.

There’s no doubt that in every heart on Earth, there’s a soft spot for Mars. How could you not love the “Red Planet”, the planet that gave us Martians, the planet so close – yet so full of mystery?

With the recent successes of the Spirit, Curiosity and Opportunity rovers; we know more about Mars than we have ever known before. If you’re interested in information about Mars and what makes it one of the most fascinating planets in our Solar System, check out this post on Cool Facts About Mars or our 10 Facts About Mars Infographic (if reading isn’t your thing).

What Will We Cover in this Post?

In this post, we’ll briefly touch on the planet Mars, but the main focus will be on the much less popular and familiar Martian objects; Phobos and Deimos. Two of the most devious moons in our Solar System, how could you not be when you’re named after some of the scariest characters in Greek Mythology…

Why is Mars Such a Big Deal?

Mars is the fourth planet from the Sun and was named after the Roman god of war. Also frequently described as the “Red Planet”, attributed to its reddish appearance. Mars is one of the four terrestrial planets in the inner Solar System, it has a thin atmosphere composed primarily of carbon dioxide, as well as polar ice caps.

Mars is the only other planet in our Solar System (besides Earth) to have polar ice caps. These polar ice caps are so large that if both the northern ice caps (Planum Boreum) and the southern ice caps (Planum Australe) melted; the melted ice would cover the entire planet of Mars in roughly 36 feet deep of water.




OK, Tell Me About the Moons of Mars

Let’s get learning about the Moons of Mars; two extremely interesting and unfortunately, not very well-known moons. The two Moons of Mars are named Phobos and Deimos; both discovered in as early as 1877 by Asaph Hall.

These moon’s names will make you think twice about ‘what’s in a name’, thanks Rodney Dangerfield. Phobos and Deimos are each named after two famous characters from ancient Greek mythology. The name Phobos depicts panic and fear, whereas the name Deimos speaks of terror – not a welcoming foreboding.

The old story from ancient Greek mythology tells of a tale of two boys (Phobos and Deimos) who always accompanied their father (Ares, the Greek god of war) into gruesome battles and bloody wars. As time passed, Ares eventually became known as ‘Mars’ from ancient Roman mythology.

Today, Scientists and Astronomers pay tribute to the two boys who followed their father into battle by naming the two moons of Mars after them. Even though Mars is currently known for having these two moons, some in the scientific community hypothesize that there might be a few to several more unknown and hidden moon, as well.

The Moons of Mars – Phobos:

Discovered in 1877 by Asaph Hall, the moon Phobos is admittedly the larger of the two moons and is perceived to be heavily covered with craters with hooves and other materials on its sides. The body of Phobos is quite unique, as it possesses a diameter of only 13 miles, with a total mass of 1,060,000 kilograms or 2,336,899 pounds!

Being confound in Mars’ orbit, Phobos only takes 7.5 hours to complete its full cycle at the orbital speed of roughly 4,783 miles per hour!




If you’re planning to visit Phobos, make sure to bring your winter coat! The surface temperature on Phobos has been recorded to be as low as -40 degrees Fahrenheit.

Most Humans have a single perception of what a moon is. Most even think the name of Earth’s moon, is just that, the Moon (FYI – its real name is Luna). While the moons of Mars have several similar qualities as Earth’s moon, Luna, it also have many differences that make Phobos one hell of an interesting moon.

One of the most interesting facts about Phobos is that it has an extremely fast orbit period. If you were standing on Mars, Phobos would actually appear to rise two times each day. Phobos rises twice from the west horizon and sets twice in the eastern horizon each Martian day – which is very close in length to an Earth day, only 24 hours and 40 minutes!

What Will Happen to Phobos?

Sad but true, Phobos is slowly nearing its eventual doom and it doesn’t appear that there will be a Hollywood-style savior to save Phobos. Each day, Phobos is getting closer and closer to Mars, being pulled in by the larger planet and significantly stronger gravitational force of the Red Planet. In time, Phobos will be destroyed by Mars’ tidal forces, shredded to pieces or drawn in and crashing into the planet known for its blood-red coloring.

Some Scientists and Astronomers ever predict that Phobos could even break into countless pieces in its own orbit and form a ring around Mars, much like that of Saturn. Can you imagine looking up at Mars with your telescope and seeing a ring around it? How cool would that be?!

What Does Phobos Look Like?

One more surprising fact about Phobos, unlike Earth’s moon, Luna, Phobos has an irregular potato-shape, rather than spherical one like Luna. Phobos is accompanied by a large crater named Stickney and is incredible to observe. In fact, the majority of the large and bulky features of Phobos gets their names from Gulliver’s Travels!

The Dark Side of the Phobos:

Let’s not pretend like everything on Phobos is all rainbows and puppies. Phobos’s history has been a little shady and dark, to say the least. To date, Scientists and Astronomers are unable to determine exactly and accurately how this moon of Mars was formed.

Some Scientists and Astronomers hypothesize Phobos’ formation is the by-product of an asteroid, others say it formed when the Solar System was born. Unless you were there, how will we ever know?

Additionally, Phobos is also a unique and rare moon of Mars because it has a fine dusty layer present on its surface called “regolith”. A number of Scientists and Astronomers have suggested that this dusty layer will eventually be blown off from its surface, at which point, Phobos will appear to have a comet-like “tail”, how majestic!

The unique and rare qualities of Phobos have historically compelled and attracted Scientists and Astronomers to attempt a visit to this beautiful and far away moon of Mars. The former Soviet Union attempted this feat years ago by launching two of their own projects, however, both failed and only extracted limited information and data from Phobos.

Where Does Phobos Stand Now?

Despite being on our radar, so to say, for nearly 140 years, there’s still a romantic attraction to the mystery which surrounds Phobos, the potato-shaped moon of Mars. Phobos remains untouched, pure in a way different from that of Earth’s moon – no dead rovers, cruisers or even foot prints. While plans are underway to put together a project to visit this enchanting moon or Mars, we’ll have to wait and see what the future holds for this mysterious moon.

The Moons of Mars – Deimos:

Also discovered in 1877 by ol’ Asaph Hall, Deimos is without a doubt the smaller of the two moons of Mars. As in the case of its “twin moon”, Phobos; Deimos also has a dusty “regolith” layer covering its surface and the majority of this moon is covered with rocky materials.




The physical features of Deimos are far different from that of Phobos; only 7.7 miles in diameter, 1,476,000,000,000 metric tons in mass and a total orbital time of 30 hours. Exactly the same as its brother-moon Phobos, Deimos is an extremely cold moon; with recorded temperatures as low as -40 degrees Fahrenheit.

What Does Deimos Look Like?

Similar to Phobos, Deimos isn’t like that of Earth’s spherical moon, Luna. Deimos is more similar to a C-type asteroid; uneven in its shape and uncommon to observe and think of as a moon.

Interestingly, Deimos, unlike Phobos, has a naturally circular orbital cycle around Mars. While this hasn’t always been the case, way back in the early days of Deimos’ discovery, its orbital cycle was up in the air (pub intended) and Scientists and Astronomers weren’t certain of its orbital path. Nevertheless, Deimos circles its host planet Mars in a near perfect circle now and is a wonderful sight to observe!

What Would it be Like on Deimos?

Wouldn’t it be fun to visit the moons of Mars; Deimos or Phobos? Either moon would provide the adventure of a lifetime and the perfect place to establish your moon-house and wake up each morning with a cup of Martian coffee and a view of the red planet!

However, you might be interested in knowing a vital characteristic each of these breathtaking moons of Mars possess; both moons practically have no atmosphere whatsoever.

The primary reason Deimos and Phobos don’t have an atmosphere is largely agreed upon by the scientific and astronomic circles as lacking the needed and required volatiles present to actually form an atmosphere.

Even if these glorious moons or Mars had the needed elements present to support an atmospheric formation, the moons have little to no gravity. If an astronomic object doesn’t have an adequate level of gravity, it won’t’ be able to maintain and build an atmosphere before it gets blown away and destroyed by solar winds and other phenomena.

The Lone Unknown, Deimos

Many Scientists and Astronomers are of the opinion that Deimos may very well have been part of a cluster of asteroids and other astronomic objects which collided with Mars. This fortunate event, while full of devastation and destruction by way of the impact, helped form on the moons of Mars.

It’s regrettable to note that Deimos has never been formally visited by any space program, with the sole or primary focus of the mission revolving around the study of Deimos. Some country’s space programs have accommodated their mission to include flying by and observing Deimos from afar.

Deimos is a very interesting moon, many is the scientific and astronomic communities argue the need to continue observing Deimos, even if simply through telescopes. If nothing else, additional data and observation will help us formulate and hypothesize various theories about the details, characteristics and history of the mysterious moon of Mars; Deimos.

Where Does Deimos Stand Now?

It’s most unfortunate that the majority of prior missions to Mars have paid minimal to no attention to the smaller moon of Mars, even when spacecraft and rovers are so close they’re able to take stunning images and outline extremely detailed maps of Mars.

However, there’s good news to share and we couldn’t be more excited to hear that there are plans underway to ‘possibly’ get a little closer to studying Deimos up close and personal. Several prominent members of the scientific and astronomic communities have proposed various missions to study Deimos and traction is being made.

Special missions entitled “Phobos and Deimos and Mars Environment” (PADME) and “OSIRIS-REx 2” are in the preliminary and development stages. Fingers crossed that it’s in the very near future that we’ll be making our way to Deimos to unravel the mysteries of this uncharted moon of Mars!

To the Moons of Mars; We Bid Thee Adieu.

The moons of Mars have always been the inspiration behind endless amounts of fascination, speculation, culture, entertainment and event mystery. While plans to visit these moons are underway, they’re in the early stages of planning and it remains uncertain whether or not these missions will leave the ground.




Nonetheless, as a member of the scientific or astronomic community, it’s our duty to publicly support these missions, they’re critical to furthering our understanding of our Solar System and the ecosystem around the red planet.

Social Sharing is Caring!

Please feel free to leave questions or comments below, everyone would love to know what you think and if the resources required to visit and study the two moons of Mars would be worthwhile. And why not hit a social button or two and let your friends know what you think!

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