This is a montage of planetary images taken by spacecraft. Included are (from top to bottom) Mercury, Venus, Earth (and Moon), Mars, Jupiter, Saturn,Uranus and Neptune. The spacecraft responsible for these images are as follows: Mercury was photographed by Mariner 10. Venus was imaged by the Magellan spacecraft's radar. Earth and its Moon were photographed by Galileo. Mars Global Surveyor took the image of Mars. Jupiter was photographed by Cassini as it travelled to Saturn. Saturn, Uranus and Neptune images were taken by the twin Voyager spacecraft. Pluto is not shown. No spacecraft has visited Pluto and it is too small and distant for good photography. The inner planets - Mercury, Venus, Earth, Moon, and Mars - are roughly to scale to each other; the outer planets - Jupiter, Saturn, Uranus, and Neptune - are roughly to scale to each other. But the actual size differences between the inner and outer planets is not to scale. Actual diameters: Sun 1,390,000 km, Mercury 4,879 km, Venus 12,104 km, Earth 12,756 km, Moon 3,475 km, Mars 6,794 km, Jupiter 142.984 km, Saturn 120,536 km, Uranus 51,118 km, Neptune 49,528 km, Pluto 2,390 km. Image Credit: NASA/JPL.