Phobos doomed Moon of Mars is the largest natural satellite of the Red planet. Is doomed because in 100 million years or so, will likely be shattered forming a dusty-rocky ring around Mars. Image credit: HiRISE, MRO, LPL (U. Arizona), NASA
The larger moon, Phobos, is indeed seen to be a cratered, asteroid-like object in this stunning color image from the Mars Reconnaissance Orbiter, recorded at a resolution of about seven meters per pixel.
But Phobos orbits so close to Mars – about 5,800 kilometers above the surface compared to 400,000 kilometers for our Moon – that gravitational tidal forces are dragging it down. In 100 million years or so Phobos will likely be shattered by stress caused by the relentless tidal forces, the debris forming a decaying ring around Mars.
Image credit: wikipedia