The two moons of Mars may have had a violent history, according to new model. The Red Planet may have acquired Phobos and Deimos after an object similar in size to Ceres and Vesta — two of the largest asteroids — collided with proto-Mars.
To test their study, the researchers built a new model that took into account interactions between Martian moons and then simulated how a disk of material would form around Mars suppose a collision between the planet and another large object occurred. This approach allowed the researchers to determine the ejections that would have been created after such an event.
"We used state-of-the-art models to show that a Vesta-to-Ceres-sized impactor can produce a disk consistent with the formation of Mars' small moons," said Julien Salmon, coauthor and part of the Southwest Research Institute.
"It has been proposed that Mars' moons formed from a disk produced by a large impact with the planet. However, whether such an event could produce tiny Phobos and Deimos remains unclear," reads the paper's abstract, which was published in Science Advances.
Phobos And Deimos Were Formed After A Collision
In their model, the collision caused the outer debris of the disk to form into Phobos and Deimos, said Salmon. Meanwhile, the inner debris moved inward before eventually becoming part of Mars. Phobos is currently spiraling inward as well and will crash into Mars after 50 million years or so. Deimos, on the other hand, wouldn't, because it's spiraling outward, away from the planet.
For decades, scientists have debated the origin of Mars's two moons. One model claims they may have come from the asteroid belt. Another one claims that they were created via a disk of debris around the planet. As Space notes, the moons having a circular orbit around the equator provides great indication that they were formed from impact.
What's more, moons being created following collisions is a common phenomenon in space. Our own Moon is believed to have been created after an object the size of Mars crashed into the planet billions of years ago.
Martian Moons Exploration
There are plans to visit Phobos and Deimos. The Japan Aerospace Exploration Agency is poised to begin the Mars Moons eXploration mission in 2024. A spacecraft will land on the surface of Phobos to collect a sample that'll be returned to Earth several years later in 2029. The main goal of the mission is to figure out the origins of the two moons, according to Robin Canup, of the Southwest Research Institute.
