jan 1, 1920 - Cosmic Scale

Description:

After World War I, astronomers confirmed that the thirty or forty thousand light years of easily observed stars nearest to us comprised only a minor corner of the universe.
There was not one Milky Way, as astronomers had once believed, but rather thousands and millions of galaxies, most so faint and so distant that the truth of the nebulae had long been
argued, but never before solved. The notion of island universes— galaxies, as we now say—was a bombshell. In the 1920s, humanity’s perception of the unbounded universe’s
true size increased by orders of magnitude.