Mars may get Saturn-like rings as Phobos crumbles

The demise of one of its moons may one day mean that Mars wind up with Saturn-like rings of dust and debris, researchers from the University of California, Berkeley and the City College of New York reported in Monday’s edition of the journal Nature Geoscience.

According to Popular Science and the Washington Post, previous research has revealed that the Red Planet’s gravitational forces are slowly causing its moon Phobos to crumble. What the latest study reveals, though, is that the moon’s complete destruction, which will take place in about 20 to 40 million years, could end up with its remains floating in orbit around Mars.

In their study, geologist Benjamin Black and graduate student Tushar Mittal explained that these rings could form quickly once the moon begins to break apart—and could remain around Mars for a period of between one million and 100 million years. The other alternative, they noted, is that it will simply crash into the planet’s surface, but that appears to be the less likely scenario.

Phobos is currently just 3,700 miles from the Red Planet (compared to the nearly 240,000 miles separating the Earth and Moon) and it is moving about six feet closer each century, said Popular Science. Based on the fact that the interior of the satellite is weakly held together, the researchers believe that gravity will eventually pull it apart, causing particles to form a ring.

Weak internal structure could spell doom for Phobos

Black and Mittal wrote that they analyzed the different potential outcomes based on geologic, spectral, and theoretical constraints, and found that since Phobos is made up of heavily damaged materials, its weakest parts would disperse tidally as it continued migrating towards the surface of Mars. The resulting rings would be similar in some ways to Saturn’s.

“Compared to Saturn’s rings, we expect a future Martian ring to be much smaller and contain much less material,” Black said to Popular Science. “But because that material will be spread over a smaller ring area, we predict that the initial density of a ring formed from the breakup of Phobos could rival or exceed the density of Saturn’s rings.

“Any large fragment of Phobos that is strong enough to escape tidal breakup will eventually collide with Mars in an oblique, low-velocity impact,” he and Mittal wrote. “Our analysis of the evolution of Phobos underscores the potential orbital and topographic consequences of the growth and self-destruction of other inwardly migrating moons, including those that met their demise early in our Solar System’s history.”

Should any catastrophic breakup take place, it would happen between 300 and 3,000 miles above the planet’s surface, the authors added. They suggest that future missions to the moon could shed new light on its composition and structure, and thus what ultimately will happen to it as it moves closer and closer to Mars’ surface.

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Feature Image: Tushar Mittal