When we think of ringed planets, we immediately think of what some consider the jewel of our solar system: Saturn. But one day our neighbour could have rings of its own.
A new study published in Nature Geoscience found that Mars’ biggest moon — Phobos — is slowly falling in to the planet. But instead of smashing into it, the small moon will slowly be torn apart, eventually forming a ring. But this isn’t happening any time soon: it will likely occur within 10 to 20 million years.
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“While our moon is moving away from earth at a few centimeters per year, Phobos is moving toward Mars at a few centimeters per year, so it is almost inevitable that it will either crash into Mars or break apart,” said Benjamin Black, an author of the paper, and a University of California, Berkeley postdoctoral fellow.
Though we think about Saturn when it comes to rings around planets, in fact, all of the outer planets — Jupiter, Saturn, Uranus and Neptune — have rings. Saturn’s are just the most prominent.
The rings around these planets are comprised of bits of ice, rock and dust. There are a couple of theories as to how these rings formed: one, that they are the result of ice, dust and rock being expelled after smashing into a moon, or moons (Saturn and Jupiter each have more than 60 moons); a second theory is that they are the result of asteroids or comets being captured and torn apart by the immense gravity of these giant planets.
Not all of the Phobos’ debris will end up as a ring, however: some larger pieces would fall to the surface, creating craters.