Phobos, one of the natural satellites of planet Mars, might soon become a thing of the past; long and shallow depressions have been observed on its surface that might cause its destruction. The findings of a new research highlighting its imminent failure were presented at the annual Meeting of the Division of Planetary Sciences of the American Astronomical Society at National Harbor, Maryland, this week.
Scientists have forecast that Phobos will be pulled apart in around 30 to 50 million years. Apparently, its ‘dismantling’ has already started.
It orbits its planet along the shortest distance (6,000 kilometers) any other moon in the solar system covers. The gravity of Mars is gradually pulling it in such that it approaches by around 2 meters every century. Grooves were observed on its surface that might be heralding its end.
“We think that Phobos has already started to fail, and the first sign of this failure is the production of these grooves,” says Terry Hurford from NASA’s Goddard Space Flight Center.
Hudford and his team suggest that the grooves are indications that Phobos is being distorted by tidal waves produced by the gravity between Mars and itself. This relationship exists between our moon and planet too – the two pull on each other, thereby generating tides in our oceans, and causing both heavenly bodies to be somewhat egg-shaped.
The new research says that the insides of Phobos might be a rubber pile that is not strongly held together. This interior is then allegedly surrounded by a 100-meter-thick layer of powdery regolith. A co-author of the study, Erik Asphaug of the School of Earth and Space Exploration at Arizona State University in Tempe, says Phobos “has a kind of mildly cohesive outer fabric” in this sense.
Such an interior would be deformed easily which would then cause the outer layer to readjust itself; the latter would display an elastic behaviour. This would cause an accumulation of stress that could cause the moon to fail.
If this is true, the tidal forces might be producing even more stress to cause grooves on its surface.
Stress fractures as forecast by the model of the team are equivalent to the grooves observed in images of Phobos.
Also, the fact that some grooves are younger than others indicates that the process is continuous. So, it appears that Phobos is slowly being pulled apart.