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Martian moon being torn apart by gravity

Mars moon Phobos may be slowly losing its structural integrity due to the Red Planet's gravity.

Some day in the distant future, Mars may find itself without one of its two moons. It turns out that the red planet may be cannibalizing one of its own moons. Phobos is slowly being pulled apart and within 30 to 50 million years from now the celestial body may no longer exist.

While the alleged eventual break up of the moon is occurring slowly, the final conclusion could be dramatic. Scientists believe that parallel grooves found on the surface of Phobos may be signs of structure failure caused by the gravitational pull of the Red Planet itself. If true, the gravity of Mars should continue to pull the moon apart, and one day it could literally be pulled to pieces.

Currently, researchers believe that Phobos was once hit in a cosmic collision years and years ago. This collision severely weakened the planet’s integrity, but the moon managed to stick together. Now, Mars is pulling the moon apart in its weakened state, and could one day tear off the top surface level of the moon.

Interestingly, no moon in the solar system has a closer rotation than Phobos, which orbits mars at just 3,700 miles. To put that into perspective, a flight from New York City to Paris is about the same distance. The Earth’s moon orbits at nearly 240,000 miles.

Due to the moon’s close distance to Mars, it also appears that it is slowly being drawn in towards the planet. Researchers believe that Phobos is coming about 2 centimeters closer per year. Even if Mars’ gravity doesn’t pull Phobos apart, it may end up colliding with the Red Planet in about 50 million years.

Phobos may not last that long, however, because of that suspected long-ago impact. Researchers now believe that Phobos’s inside is cracked and shattered, amounting to little more than a pile of rocks. The surface, however, is still largely intact, meaning that Mars is basically an orbiting “sack” of rocks.

If true, Mars gravity may be breaking that surface crust apart, and if so, gravity may break the planet apart long before the moon collides with the planet. How soon this surface will last will largely depend upon how thick it is. Currently, researchers believe it could be as thin as 100 meters.