NASA's Juno spacecraft has spotted the elusive fifth moon of Jupiter transiting the giant planet's Great Red Spot, giving astronomers a rare view of this small but intriguing natural satellite.
Jupiter's most famous moons are its four Galilean satellites: Io, Europa, Ganymede and Callisto, each of which is several thousand kilometers wide. Jupiter's fifth moon to be discovered, and the fifth-largest of the planet's 95 known moons, is Amalthea. It was found in 1892 by Edward Emerson Barnard, an American astronomer who was an outstanding visual observer. He also discovered Barnard's Star, as well as a host of dark nebulae.
