Phobos, the innermost satellite of Mars, is doomed. It orbits so close to its parent planet that one day, scientists predict, tidal forces on the tiny moon will begin to rip it apart. The outermost layer will probably be stripped away first, creating a dusty ring in a very short time scale – a month or even less. The moon could last for tens of millions of years, before it eventually fragments, bit by bit, and accretes onto the surface of Mars. But this won't happen in our lifetime – and probably not for 20 to 40 million more years. The object at the bottom is Mars' outermost satellite, Deimos. |