Mars will one day have rings like Saturn. Either that or it will collide with its innermost moon, Phobos. Due to the gravitational pull the Red Planet has on its satellite, Phobos is getting closer and closer at a rate about 6.5 feet (2 meters) per century. At this rate, it will take the moon 30 to 50 million years for it to collide with Mars.
However this outcome seems unlikely, given Phobos’ composition and density which, after some analysis, it is believed to be largely made out of porous, heavily damaged rock. This way, due to the gravitational pull and tidal forces of its parent planet, the satellite is believed to break apart as it gets closer to Mars.
After some simulations, scientists believe that Phobos will slowly turn to rubble and over a course of 20 to 40 million years, it will form a ring around Mars, similar to that of Saturn. In fact not only Saturn has rings in our Solar System, but all gas planets do. The difference is that Saturn’s rings are larger and more visible from Earth.
This is not the end of the story about Mars’ rings. Phobos being roughly 14 miles (22 kilometers) wide, the ring it will form will be about the same size and density of Saturn’s. But over time this dust too will settle on Mars’ equatorial belt. This process is estimated to take anywhere between 1 to 100 million years. In the end Mars will be ringless again, but a bit larger.
If humans will still be around then and we were able to colonize Mars by that time, looking up would be quite interesting. From one side of the planet, the ring would reflect the Sun’s light, making itself look like bright curve in the sky. On the other side of the planet, the ring will block light, thus becoming a dark curve in the sky. From Earth, Mars’ rings would most likely not be visible with a small telescope, given its dark material.
Phobos is the only remaining inwardly migrating moon known to exist today. The tiny, doomed moon may help scientists to better understand the evolution of the early solar system and the fate of other moons already destroyed.