As per the recent study, Mars’ moons (Phobos and Deimos), may have originated from debris left behind after an asteroid was torn apart by the planet’s gravity. Published in Icarus, the research challenges existing theories and offers insights into the moons' peculiar characteristics, such as their irregular, potato-like shapes and near-circular orbits.
Unlike typical spherical moons, the unique features of Phobos and Deimos have puzzled scientists, prompting new simulations to explore their formation.
Two competing theories on Moon formation
Two primary theories have been debated regarding the origins of Phobos and Deimos for a long time.
Captured Asteroid Hypothesis: This theory suggests Mars’ gravity captured the moons as asteroids. However, it struggles to explain their stable, circular equatorial orbits.
Collision Theory: Another hypothesis posits that the moons formed from debris created after a massive collision involving Mars.
Jacob Kegerreis, a planetary scientist at NASA’s Ames Research Center, proposes a hybrid scenario. He theorizes that an asteroid was initially captured by Mars’ gravity but was later shredded into a debris ring, which eventually coalesced into the two moons.
Supercomputer simulations support the hybrid model
Hundreds of simulations were conducted to test this hypothesis. By adjusting factors like the asteroid’s size, speed, and rotation, researchers consistently observed debris rings forming under specific conditions. Kegerreis explained that these simulations showed how such material could evolve into the moons’ circular orbits.
Upcoming mission may solve the mystery
The Japan Aerospace Exploration Agency’s Mars Moons Exploration (MMX) mission, scheduled for launch in 2026, aims to analyze samples from Phobos. This mission could determine whether the moons’ composition matches Mars, supporting the collision theory, or contains water-rich compounds, suggesting they are remnants of an asteroid.
The MMX mission’s findings could not only unravel the origins of Mars’ moons but also provide broader insights into moon formation around exoplanets, enhancing our understanding of planetary systems.
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