Moons of Mars binary asteroid that separated under tidal forces. Phobos could be a second-generation Solar System object that coalesced in orbit after Mars formed, rather than forming concurrently out of the same birth cloud as Mars. Another hypothesis is that Mars was once surrounded by many Phobos- and Deimos-sized bodies, perhaps ejected into orbit around it by a collision with a large planetesimal. The high porosity of the interior of Phobos (based on the density of 1.88 g/cm, voids are estimated to comprise 25 to 35 percent of Phobos' volume) is inconsistent with an asteroidal origin. Observations of Phobos in the thermal
Kaidun meteorite several have not been found elsewhere in nature, such as florenskyite, which has the chemical formula: FeTiP. In March 2004 it was suggested that the meteorite originated from the Martian moon Phobos. The reason Phobos has been suggested is the existence of two extremely rare alkaline-rich clasts visible in the meteorite, each of which entered the rock at different times. This suggests that the parent body would have been near a source of an alkaline-rich rock, which is in particular a product of deep differentiation. This points to Mars and one of its moons, and Phobos is more likely than