2015-11-23. Mars to lose its largest moon, but gain a ring.

posted Dec 3, 2015, 5:00 PM by Alan Gould
By Robert Sanders, UC Berkeley News. For GSS A Changing Cosmos chapter 7. Excerpt: 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  ...in 10-20 million years... 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. Just as earth’s moon pulls on our planet in different directions, raising tides in the oceans, for example, so too Mars tugs differently on different parts of Phobos. As Phobos gets closer to the planet, the tugs are enough to actually pull the moon apart, the scientists say. This is because Phobos is highly fractured, with lots of pores and rubble. Dismembering it is analogous to pulling apart a granola bar, Black said, scattering crumbs and chunks everywhere. ...Mittal said it’s not clear whether the dust and debris rings would be visible from earth, since dust does not reflect much sunlight, whereas ice in the rings of the outer planets makes them easily visible....  http://news.berkeley.edu/2015/11/23/mars-to-lose-its-largest-moon-but-gain-a-ring/