NATIONAL HARBOR, Md., Nov. 10 (UPI) -- Martian moon fail, as the kids say. New research suggests Mars' moon Phobos is slowly falling apart.
Shallow ditch-like groves running horizontally across the moon's surface represent underlying structural failures, like cracks in a sidewalk. Ultimately, scientists at NASA predict, these failures will prove to be the moon's undoing.
"We think that Phobos has already started to fail, and the first sign of this failure is the production of these grooves," explained Terry Hurford, a planetary scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Scientists previously blamed the grooves on a variety of impacts. But the marks don't appear to organize around any single crater.
Instead, new models created by Hurford and his fellow researchers, suggest the grooves are stretch marks made by tidal forces -- the gravitational push and pull of Mars and its moon.
It's the not the first time scientists have offered up such an explanation.
But the theory was previously proffered, more than a decade ago, under the assumption that Phobos is solid, through and through. Tidal forces wouldn't be strong enough to distort an entirely solid planet, the thinking went.
Scientists have since come to believe the moon's insides only to be a loose conglomeration of rubble, covered by an outer layer of dust, soil and broken rock. Under this scenario it seems logical that tidal forces might slowly break Phobos apart.
Hurford and his colleagues presented their new hypothesis on Tuesday at the American Astronomical Society's Division for Planetary Sciences meeting being held this week in National Harbor, Maryland.