A NASA study using supercomputer simulations offers a possible explanation for this long-standing Martian mystery. It suggests Mars may have gained its moons after its strong gravitational pull destroyed an asteroid.
Led by Jacob Kegerreis at NASA’s Ames Research Center, the research team proposes that Mars’ strong gravitational pull ripped apart a passing asteroid.
The team’s simulations show that after the asteroid was destroyed, its fragments were scattered into various orbits around Mars. While most fragments escaped the system, some remained in orbit.
These remaining pieces, influenced by Mars’ and the Sun’s gravity, collided, gradually breaking apart and creating more debris.
After multiple collisions, smaller chunks and debris from the asteroid likely formed a disk around Mars. Over time, some of this material may have clumped together, eventually forming Mars’ two small moons, Phobos and Deimos.
The research team used advanced computing systems to run hundreds of simulations, varying the asteroid’s size, spin, speed, and distance from Mars. Their findings show that in many scenarios, enough asteroid fragments survived and collided in orbit to provide the raw material for forming Mars’ moons.
Exploring a new explanation for the formation of Mars’ moons- Phobos and Deimos—is exciting. These are the only moons in our solar system that orbit a rocky planet besides Earth’s.
ISRO’s MOM captured the image of the biggest moon of Mars
The new model offers alternative predictions about the properties of Mars’ moons, which can be tested against traditional theories regarding a crucial event in the planet’s history.
Two main hypotheses explain the formation of Mars’ moons: one suggests they were captured asteroids, while the other proposes a giant impact on Mars created a debris disk that formed the moons.
The impact theory is supported by the moons’ near-circular orbits aligned with Mars’ equator. However, Mars’ moons, especially Deimos, are far from the planet, suggesting they may have formed farther out, challenging the idea that all material from the impact would stay close to Mars.
Examining Mars’ Moon Phobos in a Different Light
Jack Lissauer, a research scientist at Ames and co-author of the paper, said, “Our idea allows for a more efficient distribution of moon-making material to the outer regions of the disk. That means a much smaller ‘parent’ asteroid could still deliver enough material to send the moon’s building blocks to the right place.”
The upcoming JAXA’s Martian Moons eXploration (MMX) sample return mission aims to test different ideas for forming Mars’ moons. The spacecraft will survey both moons to determine their origin and collect samples of Phobos to bring to Earth for study.
Mars once had a ring billions of years ago
Journal Reference
- Jacob A. Kegerreis, Jack J. Lissauer, Vincent R. Eke, Thomas D. Sandnes, Richard C. Elphic. Origin of Mars’s moons by disruptive partial capture of an asteroid. Icarus. DOI: 10.1016/j.icarus.2024.116337
