Well, you might not have noticed, but today is the anniversary of a day with considerable symbolic significance.
On January 29th 1931, Edwin Hubble took Einstein up Mount Wilson to see the famous 100 inch telescope where Hubble had done at least two revolutionary things (with the aid of Henrietta Leavitt's remarkable work on variable stars): (1) He demonstrated that the Milky Way Galaxy, where we live, is not the entire universe, but just one of many galaxies, and (2) He confirmed (ahem, not discovered) that the universe was expanding and (with Humason...who started out as the janitor at the observatory) quantified it in what we now call "Hubble's Law".
This photo, which I borrowed from a Carnegie Institution site, shows: From left to right: Milton Humason, Edwin Hubble, Charles St. John, Albert Michelson, Albert Einstein, W. W. Campbell, and Walter Adams. Quite a group! This was taken during the ...
