“Gamow was fantastic in his ideas. He was right, he was wrong. More often wrong than right. Always interesting; … and when his idea was not wrong it was not only right, it was new.” -Edward Teller
100 years ago, our conception of the Universe was so small it’s almost laughable. We still were mired in Newtonian thought, conceiving only of the stars within our own Milky Way, with a Universe that was perceived as static and unchanging, and where the stars which made it up perhaps even lived forever. Yet today, we have a Universe that’s expanding, cooling, full of dark matter and dark energy, and had a birthday 13.8 billion years ago: the Big Bang.
More than that, we’ve been able to determine exactly how big the Universe is, where it came from, what happened before the Big Bang, and what its fate is today. We know how the elements were formed, how the stars live and die, what the Universe looks like on the largest scales, and how it got to be the way it is today.