Conducted with the help of supercomputers, NASA study proposed a new scenario for the formation of moons of Mars. It is associated with the destruction of an asteroid.
Mystery of Mars’ moons
The question of the origin of the Martian moons for a long time has not given scientists a rest. After all, Mars is the only rocky planet besides Earth that has its own companions.
Initially, the capture hypothesis prevailed in the scientific community, according to which Phobos and Deimos are asteroids captured by the Red Planet’s gravity. Such a scenario explains the asteroid-like appearance of the moons, but is poorly reconciled with their orbits. Phobos and Deimos move in nearly circular orbits that coincide with the equator of Mars. This suggests that they should have formed in the vicinity of the planet.
Therefore, in recent years, another hypothesis has gained popularity in the scientific community, according to which Phobos and Deimos were formed as a result of a process resembling the birth of the Moon. The giant impact is thought to have ejected so much material that a disk was formed around Mars, which then formed its moons.
This scenario explains the orbits of the Martian moons well. But, according to scientists, the disk formed by the big impact should have been located near the Red Planet. And this is inconsistent with Deimos, which is quite far from Mars.
Destroyed asteroid
In an attempt to solve the mystery of the Martian moons, a team of scientists from NASA’s Ames Research Center have enlisted the help of supercomputers. They conducted a series of simulations to test an alternative scenario that Phobos and Deimos may be the remnants of an asteroid that was once captured by Mars and then destroyed by its gravity.
The idea is that the rock fragments formed in such a scenario would have been scattered in various orbits around Mars. More than half of them would eventually go into outer space, but some remained in the vicinity of the planet. Then, under the gravity of Mars and the Sun, some of the remaining asteroid fragments would begin to collide with each other. Each collision further crumbled them and formed even more debris.
Many collisions later, smaller pieces and debris from the former asteroid formed a disk around the planet. Over time, some of this material stuck together to form two small moons, Phobos and Deimos.
According to scientists, to test the realism of such a scenario, they ran hundreds of different simulations of a close encounter, varying the size, rotation, speed and distance of the asteroid as it approached the Red Planet. The team used its high-performance open-source computing code called SWIFT and Durham University’s supercomputers to study in detail both the initial breakup and, using a different code, the subsequent orbits of the debris.
In a paper published on November 20 in the journal Icarus, the researchers reported that in many of the scenarios they tested, enough asteroid fragments survived and began colliding in orbit to serve as the raw material for moon formation.
How right they are, we may find out soon enough. Clarifying the origin of the moons of Mars is the main goal of the Japanese MMX mission. It will be expected to take a sample of Phobos’ soil, which will then be delivered to Earth. Its analysis will determine if it is of asteroid origin, or if it is composed of the same matter as Mars. MMX is scheduled to launch in 2026, with Phobos soil delivery in 2031.
Provided by NASA
