Travelers In The Night

Ganymede was discovered by Galileo Galilei using his new telescope in 1610. He observed it to be a faint point of light orbiting the planet Jupiter. This discovery along with 3 of Jupiter's moons was the first instance of objects being observed to be orbiting another planet. Now that we know that Ganymede has a substantial salty ocean one has to wonder if some type of microbes might be living there.