Jupiter’s Moons: Family Portrait

This montage shows the best views of Jupiter's four large Galilean satellites as seen by the New Horizons spacecraft during its flyby of Jupiter in late February 2007. The four moons are, from left to right: Io, Europa, Ganymede and Callisto. The images have been scaled to represent the true relative sizes of the four moons and are arranged in their order from Jupiter. Io, 2,260 miles (3,640 kilometers) in diameter, was imaged at 03:50 Universal Time on Feb. 28 from a range of 1.7 million miles (2.7 million kilometers). Europa, 1,938 miles (3,120 kilometers) in diameter, was imaged at 01:28 Universal Time on February 28 from a range of 1.8 million miles (3 million kilometers). New Horizons obtained data on Europa's surface composition and imaged subtle surface features. New Horizons spied Ganymede, 3,268 miles (5,262 kilometers) in diameter, at 10:01 Universal Time on February 27 from 2.2 million miles (3.5 million kilometers) away. Callisto, 2,995 miles (4,820 kilometers) in diameter, was imaged at 03:50 Universal Time on February 28 from a range of 2.6 million miles (4.2 million kilometers).