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
A New Theory of the Earth A New Theory of the Earth A New Theory of the Earth was a book written by William Whiston, in which he presented a description of the divine creation of the Earth and a posited global flood. He also postulated that the earth originated from the atmosphere of a comet and that all major changes in earth's history could be attributed to the action of comets. It was published in 1696 and was well received by intellectuals of the day such as Isaac Newton and John Locke. The book is organized as follows: In the introduction, Whiston discusses the Mosaic