Close up of Ganymede, one of the moons of Jupiter, 1979.
© National Aeronautics & Space Administration / Science & Society
This photograph taken by Voyager 2 shows the site of an impact on the icy surface of Ganymede which produced a crater and sprayed clean ice from below the surface over the landscape. Ganymede is Jupiter's largest moon and the largest known planetary satellite in the solar system. It is larger than the planets Mercury and Pluto, and is an icy world with some regions scarred by impact craters and others with parallel ridges and grooves formed by unknown tectonic proceses. Ganymede has its own magnetic field, and is thought to have a molten iron core. NASA's two Voyager spacecraft were launched in 1977 to explore the planets in the outer solar system. Voyager 2 pased Jupiter in 1979 Saturn (1981), Uranus (1986) and Neptune (1989).