What do we know about Mars' mysterious second moon, Deimos?

The photo is a hyperspectral image, which is a type of photo that observes in a range of colours beyond the limits of the human eye

On a flyby of Mars, the European Space Agency (ESA) captured a rare photo of its second moon - but what do we know about it?

It's called Deimos, and is much smaller and more mysterious than Phobos, the first moon of Mars.

The pictures were taken by the ESA's Hera mission, which is on its way to an asteroid called Dimorphos as part of efforts to make our planet safer.

Hera was able to get up to 1000km away from Deimos - which is actually pretty close in space terms!

So here's five facts about Deimos, Mars' most mysterious moon.

1. It's tiny and an unusual shape

Small, lumpy, and irregular, Deimos is not a neat round shape like our own Moon closer to home.

It has also got lots of craters caused by impacts to its surface, which leads to an eerie effect around the moon.

Because its gravity isn't that strong, the dust and and debris float away from the surface which is picked up by the gravitational pull of Mars.

This keeps a spooky ring of dust and debris around Mars in the same area in which Deimos orbits.

The moon is pretty tiny by space proportions - Deimos is just 9 x 7 x 6.8 miles in size (15 x 12 x 11kms) according to Nasa.

This image of Deimos was taken by a Nasa orbiter back in 2009

2. It's named after the son of a Greek god

In Greek mythology, Deimos is one of the sons of the Greek god of war, Ares, whose other son is Phobos.

Many of these myths around Greek gods were adapted for Roman gods too, and the Roman god of war is actually called Mars!

Deimos was discovered on 11 August 1877 by astronomer Asaph Hall, who gave the moon its name.

3. It's tidally locked to Mars

Deimos rotates in exactly the same time as it takes to orbit Mars, meaning that you'd only see one side of the moon if you gazed at it from the planet's surface.

This means that the side of the moon seen in this new photo would never be visible to anyone who saw it from Mars... not that there's anyone on the red planet that we know of!

This was taken by the UAE Space Agency's Emirates Mars Mission Hope Probe in 2023

4. We don't quite know how it's formed

Scientists are still yet to set on one explanation as to how Deimos was formed, but there are a few theories.

One is that Deimos, and its brother Phobos, were asteroids that got caught in the gravitational pull of Mars, and have been stuck there since.

Another suggestion is that they formed like our own Moon, by a large object hitting the planet, and the smashed rock and debris from the impact 'gluing' together to make Deimos.

More recently, some scientists have suggested that Deimos and Phobos could have actually been one asteroid that was torn apart into two separate moons.

Musician and astrophysicist Sir Brian May (bottom left) was part of the team responsible for the mission that took the new photos

5. This new photo has a rather famous face to thank

Among the scientists celebrating the new photos at the ESA is rock star Sir Brian May, who played guitar in the band Queen.

Queen are famous for big songs you might have heard like Bohemian Rhapsody and We Will Rock You.

Sir Brian is the Honorary Mission Advisor of the ESA's Hera mission, as well as an astrophysicist in his own right.

Brian May is not just a rock legend and campaigner for badgers he's also a space scientist too