'Telescopic Appearance of the Moon', c 1851.
© Science Museum / Science & Society Picture Library
Astronomical diagram drawn and engraved by John Emslie, showing some of the craters and seas of the Moon. 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 of the Moon. One of them, the Sea of Tranquility, was chosen by NASA as the landing site for Apollo 11, the first manned mision to land on the Moon. Published by James Reynolds (174 Strand, London).