Mars’s moon Phobos may someday turn back into a ring around the planet

By Leah Crane

NASA/JPL-Caltech/GSFC/Univ. of Arizona

For Mars’s moon Phobos, it’s dust to dust. There is evidence that the misshapen little moon has gone through a cycle of being smashed up and spreading into a ring around Mars before coalescing into a solid moon again.

This ring-moon cycle was proposed in 2017, and new simulations by Matija Ćuk at the SETI Institute in California, and his colleagues show that such a cycle for Phobos may have forced Mars’s other moon, Deimos, …