Mars. Wikipedia
Mars has two moons, Phobos (Phobos, Phobos) and Deimos (Deimos).
Their appearance is irregular and very small. For a long time, they were thought to be captured asteroids. Judging by their appearance and composition, this makes sense. But one thing is confusing. Their orbits are all located on the equatorial plane of Mars, both are nearly circular, both are very close to Mars, and all travel in the same direction. The orbital arrangement of captured asteroids is usually random.
Phobos. Wikipedia
So some people think that they are produced by celestial bodies hitting Mars. The massive impact would form a disk of debris in orbit around Mars, just like the birth of the Moon. The moons produced by this mechanism will orbit the planet's equatorial surface. But this mechanism would produce a large moon, which Mars does not.
Recently, some scientists have used new simulation methods to demonstrate what Mars might look like after an impact. The results show that this process did indeed create a third moon for Mars, but the largest and innermost moon eventually disintegrated due to the gravitational pull of Mars.
Deimos. Wikipedia
Mars is covered with craters. In the northern hemisphere of Mars, there is a basin called Burroris, which occupies almost the entire northern hemisphere of Mars and 40% of the total surface area. What created this basin was likely to be a huge impact. The impact event occurred about billions of years ago, and it produced far more debris than the total amount of material in the two Phobos today.
Scale maps of Mars, Phobos, and Phobos. Relatively speaking, no planet has ever been so close to its moons. Wikipedia
A recent paper published in the journal Nature Earth Science suggests that the burroris Basin created a very dense debris disk for orbit around Mars. Based on the impact parameters, thousands of years later, in an orbit very close to the surface of Mars, a large satellite with a diameter of at least a hundred kilometers appeared. Under the influence of its gravitational pull, the periphery of the fragment disk became unstable, and Phobos and Phobos were born.
Topographic map of the martian surface. The entire blue part of the Northern Hemisphere is the Burroris Basin. Wikipedia
But about 5 million years later, the giant moon was torn apart by the tidal effects of Mars' gravity. Only two other small satellites remain to orbit Mars.
In the distant past, Phobos and Phobos once had an older brother, and it existed for at least millions of years. In a few billion years, Phobos will follow suit. Future scientists may only be able to reconstruct the Martian past by relying on Phobos and the basins on Mars.