Timeline of astronomy Rectification of Planetary Theory", eliminated the need for an equant by introducing an extra epicycle, departing from the Ptolemaic system in a way very similar to what Copernicus later also did. Ibn al-Shatir proposed a system that was only approximately geocentric, rather than exactly so, having demonstrated trigonometrically that the Earth was not the exact center of the universe. His rectification is later used in the Copernican model. Nicolaus Copernicus publishes "De revolutionibus orbium coelestium" containing his theory that Earth travels around the Sun. However, he complicates his theory by retaining Plato's perfect circular orbits of the planets. A brilliant
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