Mars has two moons: Phobos and Deimos. (Artist's impression) © imago images/Anterovium
The Martian moon Deimos is being closely examined by the "Hope" space probe. It turns out that it was apparently created differently than previously assumed.
Dubai – Deimos is one of two moons orbiting the planet Mars. Because of Deimos' irregular shape, a common theory is that the Moon is an asteroid "captured" by Mars through its gravity. This theory also exists for the larger Martian moon Phobos. But new observations of the Martian moon Deimos by the space probe "Hope" seem to throw this explanatory approach overboard.
"Hope" is a space probe of the United Arab Emirates and has been in orbit around Mars since February 2021. The scientific goal of the "Hope" mission was to observe the seasonal changes in the atmosphere of Mars as well as weather patterns. When there was enough fuel left after the completion of this research, the spacecraft's engines were ignited to put it into orbit that would allow several flybys of the little-explored moon Deimos.
Martian moon Deimos in the sights of "Hope": But not a captured asteroid?
On 10 March, "Hope" flew past the Martian moon Deimos for the first time and examined it with its three instruments. The analysis of the data shows something surprising: Apparently, the Martian moon Deimos consists of the material that is also known from the surface of the red planet. It's not the kind of carbonaceous rock that many asteroids are made of.
From this, the researchers involved conclude that Deimos is made of the same material that makes up Mars. "If there was carbon or organic matter, we would see it in specific wavelengths," Hessa Al Matroushi, the principal investigator of the Hope mission, told Nature. Al Matroushi presented the results at a meeting of the European Geosciences Union in Vienna on 24 April.
Was the moon Deimos once a part of Mars?
The Martian moon Deimos has a diameter of about 12.4 kilometers and is in a bound rotation with Mars. This means that he always faces the same side of the red planet. However, due to its orbit, "Hope" was now able to see the side of the moon that was not visible from the surface of Mars and take a closer look at the small celestial body.
It seems that a new theory must now be developed as to how Deimos became a moon of the planet Mars. It is possible that the small moon broke away from the red planet at some point in the past. It is possible that Deimos and also Phobos were formed when another celestial body collided with Mars and broke out part of Mars. This theory would not be so unlikely – after all, this is how the moon that orbits the earth was formed more than four billion years ago. (tab)