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Mars' Moon Phobos is Being Slowly Ripped Apart

posted by martyb on Thursday November 12 2015, @08:50PM   
from the time-and-tide-waits-for-no-man dept.

Phoenix666 writes:

Orbiting a mere 3,700 miles (6,000 kilometers) above the surface of Mars, Phobos is closer to its planet than any other moon in the solar system. Mars' gravity is drawing in Phobos, the larger of its two moons, by about 6.6 feet (2 meters) every hundred years. Scientists expect the moon to be pulled apart in 30 to 50 million years.
...
Phobos' grooves were long thought to be fractures caused by the impact that formed Stickney crater. That collision was so powerful, it came close to shattering Phobos. However, scientists eventually determined that the grooves don't radiate outward from the crater itself but from a focal point nearby.

More recently, researchers have proposed that the grooves may instead be produced by many smaller impacts of material ejected from Mars. But new modeling by Hurford and colleagues supports the view that the grooves are more like "stretch marks" that occur when Phobos gets deformed by tidal forces.

Alas, far too long to prevent the base being overrun.

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Original Submission

• Roche limit (Score: 2, Informative) by korger on Friday November 13 2015, @06:57AM

  by korger (4465) on Friday November 13 2015, @06:57AM (#262538)

  The distance within which a celestial body (satellite, asteroid or comet) disintegrates due to the planet's tidal forces is called the Roche limit [wikipedia.org]. In the case of Mars and Phobos, this limit is 5,466 km center to center. The current distance of Phobos from Mars is 9,234 km in pericenter. If this distance were reduced by a steady 2cm/year, then Phobos would reach the Roche limit in 188 million years. However, the speed of the fall is expected to accelerate, hence the lower time estimate of 30-50 million years.

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