French astronomers from the City University of Paris have found evidence that reveals the mystery of the origin of Mars’ moons Phobos and Deimos. The study was published on: portal scientific materials arXiv.
The experts’ conclusions are based on a study of photographs taken by the Mars Express spacecraft.
The origin of Phobos and its “twin” Deimos remained a mystery to scientists for many years. According to one theory, these objects may be asteroids attracted by the Red Planet. This is indicated by the chemical composition of the moons, which partially overlap with objects in the asteroid belt between Mars and Jupiter. But computer simulations were unable to reproduce such a scenario.
Another hypothesis suggests that in the distant past, Mars collided with a giant object, ejecting Phobos and Deimos from the planet. However, the fact that Phobos is chemically different from Mars makes this explanation unlikely.
In the new study, the team analyzed more than 300 images taken by the Mars Express orbiter since 2003. Scientists examined the reflection of sunlight from the Phobos surface from different angles. It turned out that the satellite did this in an unstable manner.
Astronomers also discovered that Phobos’ surface is porous, like sand. This led the team to speculate that the moon may be covered in a thick layer of dust containing particles whose shadows disappear when exposed to direct light.
Both discovered features are characteristic of a family of comets orbiting near Jupiter. Moreover, the photometric properties of Phobos matched almost perfectly those of comet 67P in this group.
Researchers have suggested that Phobos and Deimos were once a single comet caught in the gravitational pull of Mars. The planet’s gravity then split this body in half.
Earlier astronomers discovered Earth’s potential “evil twin”.