A Great Moment in Science

As this interesting post from Discover explains, it was not until 1 January 1925 that it was really "official" that Hubble had confirmed that the Andromeda and other spiral "nebulae" were really galaxies a very long way away.

It's extraordinary to think we not quite 100 years into a proper understanding of the size and nature of the universe.   (And barely 150 years into Darwinian evolution.)

No wonder humanity is, in a sense, still adjusting to all this.