How did Mars acquire Deimos and Phobos?

Mars acquired its moons, Deimos and Phobos, primarily through the process of gravitational capture of objects that were originally asteroids. This means that both moons likely originated in the asteroid belt, which lies between Mars and Jupiter. As they traveled through the solar system, they came close enough to Mars for the planet's gravity to pull them in, allowing them to become its satellites.

The characteristics of both moons support this view; they have irregular shapes and sizes, similar to certain asteroids, indicating they are not native to Mars, nor did they form from the planet's debris. Instead, their composition and orbits suggest their origins are more asteroid-like, aligning with the gravitational capture theory. This model effectively explains how these two small celestial bodies became associated with Mars as its moons.