The two moons on planet Mars could have formed from the disintegration of a larger
Phobos and Deimos, the two moons of Mars, have long been studied by astronomers, but they still hold their share of secrets Starting with that of their origin: two theories were opposed on this subject The first estimates that these two satellites are two asteroids trapped in the gravitational field of Mars Their small size (22 kilometers in diameter for Phobos and 12 kilometers for Deimos) and their very irregular shape argue in favor of this solution. Another hypothesis, however, saw it as the remnant of a giant impact that put Martian matter into orbit a few hundred million years after the planet was formed. The latter theory currently appears to have received support from the scientific community since the publication of two solid studies in 2016. Today, a team from the Swiss Federal Institute of Technology in Zurich (ETH) makes a third postulate: Phobos and Deimos would come from a single ancestor, a moon that once revolved around Mars
This new finding is the result of a computer simulation that traced the orbit of the two satellites to a long time ago And it turns out that their paths cross in one place, which suggests that they were most likely in the same place and therefore of the same ancestry. Â € œWe argue that Phobos and Deimos were born of a common origin i.e. they represent the main fragments of a lost Martian moon which was much larger and was struck by another object which was about to be split into two smaller moons, ”says Sciences et Avenir Amirhossein Bagheri of ETH Depending on the variation in the modeling parameters, the effects could have occurred between 2.7 and 1 billion years, as shown in the study published in the journal Nature Astronomy However, based on these calculations, it is difficult to know more about the appearance of this original large moon. “What we can say about the ancestor is quite limited We argue that it probably formed in situ It could orbit Mars for a long time, even billions of years, before being hit by another impactorÂ Â »Planetologist
Although simple, these results required extensive preparatory work First, the researchers had to refine the existing theory that describes the interaction between the moons and Mars, that is, to study the effect of tidal forces between them These forces lead to a form of energy conversion called dissipation, the magnitude of which depends on the size of bodies, their internal composition and above all the distances between them. The researchers used the latest results from the InSight probe, a seismic laboratory on Mars, to refine their knowledge of the interior and composition of the Red Planet, as well as measurements from other probes to analyze the two satellites of Mars
In this case, a ring could form around Mars like the one adorned with most gaseous planets including Saturn, but composed of stones rather than ice, a hypothesis that already exists Considered in 2015 by astronomers and geologists from the University of California at Berkeley, who estimated that the event would occur in 20 to 50 million years When this ring forms, it is short lived and its durability depends on how far the moon bursts very close to Mars, at about 1.2 March radius (or about 680 km), it is a narrow ring that has existed for ten million years remains and surrounds Mars However, if Phobos is destroyed further from Mars, the ring could expand and last for at least 100 million years.
The Japanese MMX mission (for Mars Moons Exploration) to bring back samples of Phobos in 2027 will allow us to better understand the composition of Phobos to determine its density Information that will be useful to refine the date of impact on the precursor moon that spawned the two satellites, and which will also serve to better understand the scenario of the end of Phobos
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Phobos, Deimos, Moon, Mars, Moons of Mars, Natural satellite
News – EN – World news – An old Martian moon at the origin of Phobos and Deimos
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– World news – An old Martian moon in the origin of Phobos and Deimos
– Were the moons of Mars, Phobos and Deimos born out of another shattered moon?