Who’s Scared of the Little Potato Moon of Mars?

Mars’s moon Phobos photobombs a photo of Mars

Sarah Marie
5 min readAug 8, 2022
Hubble image of Mars in which you can see red clay areas as well as darker areas. The planet is also tinged with an ethereal blue from the northern pole down the left side down to the southern pole and a particularly bright area of blue at around the equator on the right side. We also see one of its 2 moons, Phobos, make an appearance in orbit around the planet on the left. As this image is the compilation of 13 exposures over 22 minutes, we see thirteen little dots in a row as it orbited Mars.
NASA’s Hubble Sees Martian Moon Orbiting the Red Planet sourced from Astropix. Image Credits: NASA and ESA, Provider: Space Telescope Science Institute, Image Source:,

Welcome back to the Monday Astronomy Picture Ponderings (MAPPs) series where every Monday I normally pick one of NASA’s Astronomy Picture of the Day (APOD) entries from the past seven days to focus on in some way.

Saturday, August 6th’s NASA Astronomy Picture of the Day featured a stereo anaglyph view of Phobos, making it viewable in blue-red 3-D glasses if you have any lying around or want to DIY some. If you don’t, you can still get a basic idea of the moon’s shape and texture without them. The 3D glasses just provide more depth, which is very cool.

A lumpy, cratered rock features in the black of space. Mars’s moon Phobos looks very similar to an asteroid, because it might have been in the asteroid belt in its past, though we don’t know. This image is a stereo view, meaning that it was taken in both red and blue filters, leaving areas of red and blue around certain features. When using 3-D glasses with red and blue lenses, this images appears in 3-D showing off all its craters and lumps.
Stereo Phobos from Saturday, August 6th’s NASA Astronomy Picture of the Day. Image Credit: G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA

Now, you may be looking at the lumpy potato above and thinking that it looks nothing like our moon, so how could it be a moon? Very briefly, a moon is any naturally orbiting object around a planet (a satellite). While our moon is fairly spherical, a bright white with darker areas, not all are. In fact, there are many different types of moons. If you want to learn more about what makes a moon, a moon, feel free to check out one of my previous articles below.

Earth is actually the only planet in our solar system to have only one moon! Mars, for instance, has two: Phobos and Deimos. Mars is the Roman God of War and Phobos and Deimos are the son of Ares, the Greek God of War. Many of the astronomical bodies in our solar system are named after Roman and Greek gods and we even love to mix and match! Phobos means panic or fear and Deimos terror or dread. They often accompanied their father into battle which makes sense as war can inspire panic and terror.

Both are very small compared to our moon and look closer to lumpy potatoes. The prevailing theory for how they formed is that Mars snatched them out…



Sarah Marie

Author & Freelance Writer | Top Writer in Space | A little bit of everything: Science, books, personal development, fiction, poetry, hobbies, and art