Greetings, friends. On January 1, 1925, exactly a century ago yesterday, Edwin Hubble addressed the annual meeting of the American Astronomical Society to confirm the discovery of Cepheid variable stars in the Great Nebula in Andromeda. This announcement decisively demonstrated the existence of other galaxies beyond the Milky Way, and paved the way for our modern understanding of cosmology.
I still find it hard to believe that, in some sense, humanity’s most advanced conception of the true scale of the universe wasn’t even a century old until… yesterday. My grandfather was born into a world where even the most educated scientists weren’t certain that other galaxies existed. My paternal grandmother was only a few months old when Hubble’s bombshell settled a debate that had raged for years among the leading astronomers of the day: Just how big is our universe?
I am personally obsessed with this question. Not with the answer, I mean. I think, in this the year 2025 of the Common Era, that scientific consensus has a pretty good idea of the extent of the visible cosmos.
I mean that I am obsessed with the question. For as long as human beings have entertained abstract thought, some bright lad or lady out there has probably wanted to know: How big is the world? How far away are the sun, the moon, or the stars? Is there anything beyond them?