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 House of the Rising Sun that the song is about a woman who killed her father, an alcoholic gambler who had beaten his wife. Therefore, the House of the Rising Sun may be a jailhouse, from which one would be the first person to see the sunrise (an idea supported by the lyric mentioning "a ball and chain," though that phrase has been slang for marital relationships for at least as long as the song has been in print). Because women often sang the song, another theory is that the House of the Rising Sun was where prostitutes were detained while being treated for syphilis.