De revolutionibus orbium coelestium Earth's axis rigidly to a Sun-centered sphere. The unfortunate consequence was that the terrestrial rotation axis then maintained the same inclination with respect to the Sun as the sphere turned, eliminating the seasons." To explain the seasons, he had to propose a third motion, "an annual contrary conical sweep of the terrestrial axis". It was not until the Great Comet of 1577, which moved as if there were no spheres to crash through, that the idea was challenged. In 1609, Kepler fixed Copernicus' theory by stating that the planets orbit the sun not in circles, but ellipses. Only after Kepler's
The War of the Worlds the 20th Century, including first contact and war between planets and their differing species. There were, however, stories of aliens and alien invasion prior to publication of "The War of the Worlds". In 1727 Jonathan Swift published "Gulliver's Travels". The tale included a people who are obsessed with mathematics and more advanced than Europeans scientifically. They populate a floating island fortress called Laputa, 4½ miles in diameter, which uses its shadow to prevent sun and rain from reaching earthly nations over which it travels, ensuring they will pay tribute to the Laputians. Voltaire's "Micromégas" (1752) includes two beings from Saturn