Say hello to Phobos! In this photo snapped by NASAHubble, we were able to catch the tiny Martian moon right next to its planet, illustrating their massive size difference. Mars is about half the size of Earth, with a diameter of around 4,200 miles. Phobos is minuscule in comparison, however, measuring 17 miles in diameter at its widest point. Unfortunately for this little friend of Mars, you cannot spell “friend” without “end.” Like Icarus flying too close to the Sun, Phobos is moving a little too close to the Red Planet, approaching at a rate of six feet every hundred years. This means that it is set to crash into Mars in 50 million years, or break up into a ring like the ones that Saturn and Uranus have. But no matter what happens, Mars will not be doomed to loneliness. Mars has another moon in addition to Phobos, named Deimos. Both are thought to be captured asteroids and have a lumpy, irregular shape—unlike larger, spherical moons. Out of the two tiny Martian moons, Phobos is t...