Mars' moons may have formed from the fragments of a large asteroid.

Traditional theories regarding the origins of Mars' moons, Phobos and Deimos, fail to account for the unique characteristics of their composition and orbits. As a result, astronomers have proposed a new hypothesis suggesting that these satellites of the fourth planet from the Sun formed from debris of a large asteroid that passed dangerously close to the Red Planet. Calculations indicated that the asteroid crossed what is known as the Roche limit—the distance at which tidal forces, driven by the planet's gravity, became so intense that they tore the asteroid apart. Future space missions will help verify these scientists' findings.

2024-11-28 10:02:22https://naked-science.ru/article/astronomy/sputniki-marsa-mogli-vozn

The moons of Mars were discovered by astronomer Asaph Hall in 1877. Since then, these celestial bodies have captured attention, as their origin remains uncertain. The appearance and small size of the moons (with Phobos having a diameter of about 26 kilometers and Deimos around 16 kilometers) support the capture theory, yet do not account for the peculiarities of their nearly circular and equatorial orbits.

Typically, the trajectories of captured moons, such as Triton (Neptune's moon) or Phoebe (Saturn's moon), are elongated and inclined, and they often exhibit retrograde motion around their parent planet. This is why the giant impact hypothesis provides a more natural explanation, suggesting a "collision" of the Red Planet with another celestial object.

A new hypothesis regarding a destroyed asteroid may clarify the situation, described in the journal Icarus. Using the supercomputer at Durham University (UK), a team of researchers led by Jacob Kegerreis from NASA's Ames Research Center conducted hundreds of simulations of a large asteroid passing dangerously close to Mars.

By varying the asteroid's diameter, rotation, speed, and distance from the Red Planet during the closest approach, the scientists developed a scenario that explains both the origin and orbital characteristics of Phobos and Deimos.

The results indicated that the asteroid, while flying past Mars, was torn apart by tidal forces, and a significant portion of the debris was captured by the planet's gravity. Over time, these fragments formed a disk from which Phobos and Deimos emerged through accretion.

Since the destroyed asteroid scenario proposes a smaller mass for the parent body than the giant impact hypothesis, the conclusions of the authors of this new scientific work are considered more plausible. Additionally, less massive asteroids are more commonly found in the Solar System.

Each of the three hypotheses (capture, collision, and destroyed asteroid) can be tested through future space missions, such as the Martian Moons eXploration (MMX). Further studies will also enable scientists to analyze the surface composition, internal structures, and orbital parameters of Phobos and Deimos.