Because of the low Phobos rotation rate relative to its orbital rate, tidal locking reduces its orbital radius of about 20 meters per century. At 11 million years, it will either impact the surface of Mars or, more likely to divide into a planetary ring. [26] In view of Phobos in the wrong form, and provided that it is a bunch of garbage (especially in the Mohr-Coulomb body), it was estimated that Phobos is currently stable in relation to the tidal forces. However, it is assumed that Phobos will be Roche limit for the garbage pile when it drops on the orbital radius of just over 2000 km to 7100 km. At the distance of Phobos likely will begin to disperse and form short-lived ring system around Mars. The rings themselves will continue to spiral slowly to Mars.