In the past 4 billion or so years, scientists believe this has occurred three to seven times, with each time resulting in a smaller moon.
“Each time a moon broke apart and reformed from the resulting ring, its successor moon would be five times smaller than the last, according to the model, and debris would have rained down on the planet, possibly explaining enigmatic sedimentary deposits found near Mars’ equator,†NASA said.
A similar study was released back in 2015, which claimed once Phobos broke apart it would form a ring around Mars.
None of us will be around to see Phobos eventually form a ring around Mars, but it’s looking more likely to happen. Once it does, it’ll continue its cycle until, eventually, Phobos may not exist at all. Either way, it’ll sure be a sight for future Mars colonizers.
Article source: https://www.technobuffalo.com/2017/03/25/mars-had-rings-may-have-rings-in-the-future/