Mars is doing serious damage to the closest of its two moons, Phobos, which is showing signs of wear and tear as its drawn closer to its host planet.

According to Discovery News, new research presented at the American Astronomical Society's (AAS) annual Planetary Sciences meetings detailed stress fractures appearing on Phobos' surface. The fractures were previously theorized to be the remnants of an asteroid clash, but now they appear more likely to be caused by Mars' gravitational pull.

"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 in Greenbelt, Md., said in a news release.

Phobos orbits Mars closer than any other moon in the solar system does with its host planet. Past studies have shown Phobos gradually moving closer and closer to Mars, but now it appears that motion is tearing the moon apart.

"We think the grooves are signs that this body is starting to break apart tidally and that these are the first evidence of the tidal deformations of Phobos," Hurford told Discovery News. "Eventually, Phobos will be ripped apart before it reaches Mars' surface."

The research also suggests that Phobos is nothing more than rubble below the surface.

"The funny thing about the result is that it shows Phobos has a kind of mildly cohesive outer fabric," Erik Asphaug, a study co-investigator at the School of Earth and Space Exploration at Arizona State University, said in the release. "This makes sense when you think about powdery materials in microgravity, but it's quite non-intuitive."