THE names of the planets reflect the history of the Earth. Five Mercury, Venus, Mars, Jupiter and Saturn were known in antiquity. The titles they now bear were chosen by the most powerful and influential civilisation of the classical era, Rome. The others, Uranus, Neptune and, until its demotion in 2006, Pluto, were discovered by Westerners, who saw themselves as Rome’s heirs and decided they would carry on the tradition (though Uranus is named after a Greek god, rather than a Roman one).