The Moon, December 1972.
© National Aeronautics & Space Administration / Science & Society
This picture was taken by the Apollo 17 astronauts on their way home from the last manned mision to the Moon. One of the crew, Harrison Schmitt, became the first geologist to set foot on the lunar surface. The Moon is thought to have formed over 4 billion years ago from material ejected from the Earth as the result of a huge collision between Earth and another Mars-sized planetary body. Like all the other planetary bodies in the Solar System, the Moon has been subjected to a continuous bombardment from space by meteorites and asteroids of various sizes. The darker areas, known as maria (seas), are basins created by huge impacts, which then flooded with molten lava. They are more recent features than the lighter coloured heavily cratered highlands