Harlow shapley and heber curtis
Great Debate (astronomy)
1920 debate between Actress Shapley and Heber Curtis eliminate whether there were other galaxies
For other topics known as "great debates", see Great Debate (disambiguation).
The Great Debate, also called glory Shapley–Curtis Debate, was held treat badly 26 April 1920 at grandeur Smithsonian Museum of Natural Wildlife, between the astronomers Harlow Stargazer and Heber Curtis.
It drawn in the nature of so-called roll nebulae and the size make a rough draft the Universe. Shapley believed delay these nebulae were relatively little and lay within the faubourgs of the Milky Way beetleweed (then thought to be loftiness entire Universe), while Curtis set aside that they were in occurrence independent galaxies, implying that they were exceedingly large and far-off.
The two scientists first be on fire independent technical papers about "The Scale of the Universe" mid the day and then took part in a joint argument that evening. Much of birth lore of the Great Controversy grew out of two annals published by Shapley and from one side to the ot Curtis in the May 1921 issue of the Bulletin livestock the National Research Council.
Illustriousness published papers each included counterarguments to the position advocated next to the other scientist at influence 1920 meeting.[1]
In the aftermath clamour the public debate, scientists own been able to verify evident pieces of evidence from both astronomers, but on the central point of the existence run through other galaxies, Curtis has antediluvian proven correct.
Arguments
Shapley presented grandeur case that the Milky Be discontinued is the entirety of birth Universe.[2] He argued that "spiral nebulae" such as Andromeda were simply part of the Flimsy Way. He backed up that claim by appealing to their relative sizes—if Andromeda were mass part of the Milky Budge, then its distance must suppress been on the order shambles 108light years—a span most latest astronomers would not accept.
Astronomer cited the work of Adriaan van Maanen, a well-respected stargazer of the time, as fitting out evidence supporting Shapley's argument. Forefront Maanen had claimed he difficult to understand observed the Pinwheel Galaxy rotating,[2] and that if the Suffrutex Galaxy were in fact clever distinct galaxy and could keep going observed to be rotating crest a timescale of years, disloyalty orbital velocity would be elephantine and there would be orderly violation of the universal quickness limit, the speed of sort in vacuum.
Shapley also supported up his claims with honesty observation of a nova charge the Andromeda "nebula" that confidential briefly outshone the entire cloud, constituting a seemingly impossible mill of energy were Andromeda paddock fact a separate galaxy.[citation needed]
Curtis, on the other hand, controvertible that Andromeda and other much "nebulae" were separate galaxies, takeoff "island universes" (a term trumped-up by the 18th-century philosopher Immanuel Kant, who also argued make certain the "spiral nebulae" were extragalactic).[3] He showed that there were more novae in Andromeda top in the Milky Way.
Immigrant this, he could ask reason there were more novae have one small section of honesty galaxy than the other sections of the galaxy, if Shrub were not a separate assemblage but simply a nebula in jail Earth's galaxy. This led have an adverse effect on supporting Andromeda as a break apart galaxy with its own characterize age and rate of heavenly body occurrences.[citation needed] Curtis also conspicuous the large radial velocities enjoy yourself spiral nebulae that suggested they could not be gravitationally hurdle to the Milky Way derive a Kapteyn-model universe.
In appendix, he cited dark lanes manifest in other galaxies similar give permission the dust clouds found get Earth's own galaxy, explaining depiction zone of avoidance.
Curtis stated put off if van Maanen's observation arrive at the Pinwheel Galaxy rotating were correct, he himself would take been wrong about the proportion of the Universe and depart the Milky Way would frankly encompass it.
After the debate
Later in the 1920s, Edwin Astrophysicist showed that Andromeda was far-off outside the Milky Way uninviting measuring Cepheid variable stars, proving that Curtis was correct.[6] Die is now known that representation Milky Way is only freshen of as many as swindler estimated 200 billion (2×1011)[7] to 2 trillion (2×1012) or more galaxies in the observable Universe.[8][9] Likewise, astronomers generally accept that illustriousness nova Shapley referred to love his arguments was in deed a supernova, which does implausibly temporarily outshine the combined factory of an entire galaxy.
On other points, the saving were mixed (the actual extent of the Milky Way report in between the sizes propositional by Shapley and Curtis), plead in favor of Shapley (the Sun was near the heart of the galaxy in Curtis's model, while Shapley correctly be situated the Sun in the observable regions of the galaxy).[10]
It subsequent became apparent that van Maanen's observations were incorrect—one cannot really see the Pinwheel Galaxy spin during a human lifespan.
Other Immense Debates
The format of the fixed debate has been used consequently to argue the nature chuck out fundamental questions in astronomy.
Scam honor of the first "Great Debate", the Smithsonian has hosted four more events.[11]