Why Mars Is Destroying Its Moon
Fifty million years from now, Mars is likely to be left with just one moon. Its larger moon Phobos will be torn apart by the planet.
Christian Science Monitor reports that gravitational tidal forces exerted on the moon by the Red Planet are causing structural faults in Phobos that would make it yield. Researchers concluded that the grooves and cracks are not a result of massive crater, called the Stickney crater, but due to the forces exerted by Mars.
"We think that Phobos has already started to fail, and the first sign of this failure is the production of these grooves," said Terry Hurford of NASA's Goddard Space Flight Center in Greenbelt, in a press release.
The study has also led to researchers reimagining the structure of Phobos, revising existing notion that Phobos is a solid moon. Given that Mars exerts weak forces on it, researchers believe that the fractures indicate Phobos could a rubble pile held together by 100 meters of powder.
The theory fits well with the observations made. Researchers surmise that a relatively elastic outer layer explains the stress grooves, some of which are said to be younger than the rest. This indicates an ongoing process and not an impact crater is responsible for what is happening to the moon.
While 50 million years may seem long enough for the moon to be around, it is not that long on celestial scales. The phobos episode has also reminded scientists of Neptune's moon Triton which is also slowly falling inward.