Shapley-Curtis debate
The great debate , also known as The Great Debate ( english The Great Debate ), bundled the discussions at the beginning of the 20th century, which eventually led to a new understanding of the nature of galaxies and the size of the universe led.
The discussion between astronomers Harlow Shapley and Heber Curtis took place on April 26, 1920 in the Baird Auditorium of the National Museum of Natural History in Washington . It revolved around the size of the Milky Way and the question of whether the galaxies known at the time as spiral nebulae are small objects in the Milky Way or much further away and separated from the Milky Way. On that day, the two scientists presented independent technical lectures on the scale of the universe , which were followed by a public discussion that evening.
Shapley argued that the Milky Way is much larger than previously thought by most astronomers, and that the Sun is not at its center. He saw spiral nebulae as gas clouds in this single huge 'galaxy'. Curtis represented a much smaller model of the Milky Way, but viewed spiral nebulae as independent objects similar to the Milky Way at great distances.
Both participants had drawn partly correct and partly wrong conclusions from the findings at the time. As far as we know today, the Milky Way is actually much larger than Curtis assumed. Later findings, for example the discovery of Cepheids in the Andromeda nebula and other galaxies by Edwin Hubble , showed that the spiral nebulae are still far outside even the great Milky Way proposed by Shapley and are independent 'islands of the world'.