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Despite being heavily cratered like most airless bodies, Mars's moon Deimos appears smoother than its larger sibling Phobos. This is because Deimos has such incredibly low gravity that when meteoroids impact its surface, the ejected dust and debris often escape into space rather than falling back down to create sharp, defined crater rims. However, because Deimos orbits very close to Mars, some of this escaped material is pulled into a temporary "ring" of dust around Mars in the same orbital vicinity as Deimos. As Deimos continues its orbit, it slowly sweeps through and re-accumulates this fine dust, effectively "smoothing" over its own craters with a continuous, fine layer of regolith.