The Andromeda Galaxy in ultraviolet

In astronomy, The Great Debate was an influential debate between the astronomers Harlow Shapley and Heber Curtis which concerned the nature of spiral nebulae and the size of the universe. The basic issue under debate was whether distant nebulae were relatively small and lay within our own galaxy or whether they were large independent galaxies. The debate took place on 26 April 1920 in the Baird auditorium of the Smithsonian Museum of Natural History. The two scientists first presented independent technical papers about "The Scale of the Universe" during the day and then took part in a joint discussion that evening. Much of the lore of the Great Debate grew out of two papers published by Shapley and Curtis in the May 1921 issue of the Bulletin of the National Research Council. The published papers each included counter arguments to the position advocated by the other scientist at the 1920 meeting. Download high resolution version (6200x6200, 4227 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (6200x6200, 4227 KB) Wikipedia does not have an article with this exact name. ... For other uses, see Astronomy (disambiguation). ... Harlow Shapley in his earlier years. ... Heber Doust Curtis (June 27, 1872 – January 9, 1942) was an American astronomer. ... An example of a spiral galaxy, the Pinwheel Galaxy (also known as Messier 101 or NGC 5457) A spiral galaxy is a galaxy belonging to one of the three main classes of galaxy originally described by Edwin Hubble in his 1936 work “The Realm of the Nebulae”[1] and, as... The Triangulum Emission Nebula NGC 604 The Pillars of Creation from the Eagle Nebula For other uses, see Nebula (disambiguation). ... For other uses, see Universe (disambiguation). ... For other uses, see Galaxy (disambiguation). ... is the 116th day of the year (117th in leap years) in the Gregorian calendar. ... Year 1920 (MCMXX) was a leap year starting on Thursday (link will display 1920) of the Gregorian calendar. ... The Smithsonian castle, as seen through the garden gate. ... Inside the National Museum of Natural History, underneath the rotunda. ... Year 1921 (MCMXXI) was a common year starting on Saturday (link will display the full calendar). ... The National Research Council (NRC) of the USA is the working arm of the United States National Academy of Sciences and the United States National Academy of Engineering, carrying out most of the studies done in their names. ... This article is about the profession. ...

Harlow Shapley

Shapley was arguing in favor of the Milky Way as the entirety of the universe. He believed galaxies such as Andromeda and the Spiral Nebulae were simply part of the Milky Way. He could back up this claim by citing relative sizes—if Andromeda and such were not part of the Milky Way, then the distance to it be in the order of 10⁸ light years—a span most astronomers would not accept. Adriaan van Maanen was also providing evidence to Shapley's argument. Maanen was a well respected astronomer of the time who said he had observed Andromeda rotating. If Andromeda was in fact a distinct galaxy and could be observed to be rotating, there would clearly be a violation of the universal speed limit, the speed of light. Image File history File links Shapley_small. ... Image File history File links Shapley_small. ... For other uses, see Milky Way (disambiguation). ... The Andromeda Galaxy (IPA: , also known as Messier 31, M31, or NGC 224; older texts often called it the Great Andromeda Nebula) is a spiral galaxy approximately 2. ... A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ... For other uses, see Astronomy (disambiguation). ... Adriaan van Maanen (March 31, 1884, Sneek – January 26, 1946, Pasadena) was a Dutch-American astronomer. ... The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness.[1] It is the speed of all electromagnetic radiation, including visible light, in a vacuum. ...

Curtis on the other side contended that Andromeda and other such nebulae were separate galaxies, or "Island universes". He showed that there were more novae in Andromeda than in the Milky Way. From this he could ask why there were more novae in one small section of the galaxy than the others. This led to supporting Andromeda as a separate galaxy with its own signature age and rate of novae occurrences. He also cited dark lanes present in other galaxies similar to the dust clouds found in our own galaxy and massive doppler shifts found in other galaxies. For other uses, see Supernova (disambiguation). ... The Doppler effect is the apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. ...

Curtis stated that if van Maanen's observation of Andromeda rotating were correct, he himself would have been wrong about the scale of the universe and that the Milky Way would fully encompass it. It later became apparent that van Maanen's observations were completely false—one can not actually see Andromeda rotate during a human lifespan. It is now known that the Milky Way is only one of hundreds of billions of galaxies in the visible universe, proving Curtis the more accurate party in the debate in that respect. On other points the results were mixed (The actual size of the Milky Way is in between the sizes proposed by Shapley and Curtis.), or in favor of Shapley (Curtis' galaxy was centered on the Sun, while Shapley correctly placed the Sun in the outer regions on the galaxy.).^[1] This article is about the measure of remaining life. ... The deepest visible-light image of the cosmos. ...

Other meanings

There is also a group based in Newcastle upon Tyne in England whose forum, also entitled The Great Debate, discusses a variety of subject including the modern picture of what it is to be human in the light of evolutionary and neuroscientific discoveries. Its chair Dr Caspar Hewett is a freelance environmental consultant. For other uses, see England (disambiguation). ...

"The Great Debate" is also the fourth track of progressive metal band Dream Theater's sixth album, Six Degrees of Inner Turbulence. Dream Theater is an American progressive metal band comprising James LaBrie, John Petrucci, Jordan Rudess, John Myung, and Mike Portnoy. ... Six Degrees of Inner Turbulence (often abbreviated to SDOIT or 6DOIT) is the sixth full-length studio album by progressive metal band Dream Theater. ...

See also

• Universe
• Galaxy
• Andromeda Galaxy
• Milky Way
• Astronomy

For other uses, see Universe (disambiguation). ... For other uses, see Galaxy (disambiguation). ... The Andromeda Galaxy (IPA: , also known as Messier 31, M31, or NGC 224; older texts often called it the Great Andromeda Nebula) is a spiral galaxy approximately 2. ... For other uses, see Milky Way (disambiguation). ... For other uses, see Astronomy (disambiguation). ...

External links

• [1] − resources related to the debate at the NASA website

The National Aeronautics and Space Administration (NASA) (IPA [ˈnæsə]) is an agency of the United States government, responsible for the nations public space program. ...

References

1. ^ Why the `Great Debate' Was Important