Mars’ largest moon, Phobos, is slowly falling toward the planet, but rather than smash into the surface, it likely will be shredded and the pieces strewn about the planet in a ring like the rings encircling Saturn, Jupiter, Uranus and Neptune.
[See also the recent report on the future break-up of Phobos, from the Division for Planetary Sciences meeting earlier this month.]
Though inevitable, the demise of Phobos is not imminent. It will probably happen in 20 to 40 million years, leaving a ring that will persist for anywhere from one million to 100 million years, according to two young earth scientists at the University of California, Berkeley.
In a paper appearing online this week in Nature Geoscience, UC Berkeley postdoctoral fellow Benjamin Black and graduate student Tushar Mittal estimate the cohesiveness of Phobos and conclude that it is insufficient to resist the tidal forces that will pull it apart when it gets closer to Mars. [More at links]