Mars's Moon Phobos Is Falling Apart

Wednesday, 11 November 2015 - 10:09AM
NASA
Solar System
Wednesday, 11 November 2015 - 10:09AM
Mars's Moon Phobos Is Falling Apart
Mars's moon Phobos is headed for a complete self-destruction, as it is slowly being pulled to pieces by the gravitational pull between the moon and Mars. Researchers recently discovered that the long, shallow grooves on its surface may be a sign that the entire planet is fracturing, and will be utterly destroyed within 30 to 50 million years.

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"We think that Phobos has already started to fail, and the first sign of this failure is the production of these grooves," Terry Hurford of NASA's Goddard Space Flight Center said in a statement.
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Phobos is closer to Mars than any other moon in the solar system, orbiting only 3,700 miles away from Mars's surface. As a result, there is an extremely strong gravitational pull between the two bodies, with Mars pulling Phobos about 6.6 feet closer every century. The gravitational pull produces potent tidal forces, which may be responsible for the moon's trademark grooves that line its surface.

Scientists originally believed that the grooves were the result of many collisions with material ejected from Mars. The notion that they were the result of tidal forces was proposed decades ago, but at the time, Phobos was believed to be solid to its core, which would mean that the stresses caused by Mars's gravity would be insufficient to cause these fractures. Now, scientists theorize that Phobos has a mildly cohesive outer layer surrounding a core of rubble that tenuously holds together, surrounded by another layer of powdery regolith that extends 330 feet.

When the researchers used this theory in their new modelling, they concluded that the tidal forces are so severely deforming the moon that the grooves are appearing as "stretch marks." A similar, although much less drastic, effect can be seen in the gravitational pull between Earth and our moon; the tidal forces not only cause the tides in the oceans, but make both our planet and the Moon slightly egg-shaped.

The scientists concluded that the grooves are the beginning of a massive structural failure within the moon, and that Phobos will be effectively disintegrated in the relatively near future. Observing this process may help us understand similar processes occurring in unobservable deep space; Neptune's moon Triton, which may meet a similar fate, is close enough to observe, but the researchers believe this phenomenon is occurring in extrasolar planets as well.

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"We can't image those distant planets to see what's going on, but this work can help us understand those systems, because any kind of planet falling into its host star could get torn apart in the same way," said Hurford.
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Via Gizmodo.
Science
Space
NASA
Solar System

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