Fom our viewpoint on Earth, the moon always shows the same side. There’s no permanently dark side of the moon, but there is a far side that we’d never seen until 1959 when the Russians put the space probe Luna 3 in orbit around the moon. But if the moon is...
When it was first discovered, in 1930, Pluto was considered to be a planet, like the other 8 planets we knew of. But as our telescopes became more accurate, astronomers began to find other large objects – in the asteroid belt between Mars and Jupiter and in the Kuiper...
