Great Debate (astronomy)

[1] In the aftermath of the public debate, scientists have been able to verify individual pieces of evidence from both astronomers, but on the main point of the existence of other galaxies, Curtis has been proven correct.

He backed up this claim by appealing to their relative sizes—if Andromeda were not part of the Milky Way, then its distance must have been on the order of 108 light years—a span most contemporary astronomers would not accept.

[citation needed] Curtis also noted the large radial velocities of spiral nebulae that suggested they could not be gravitationally bound to the Milky Way in a Kapteyn-model universe.

[5] Curtis stated that if van Maanen's observation of the Pinwheel Galaxy rotating were correct, he himself would have been wrong about the scale of the Universe and that the Milky Way would fully encompass it.

[8][9] Also, astronomers generally accept that the nova Shapley referred to in his arguments was in fact a supernova, which does indeed temporarily outshine the combined output of an entire galaxy.