100 years ago today, the New York Times reported Edwin Hubble’s definitive demonstration that Andromeda is a separate galaxy. And in that moment, millions of people began to understand that the Universe was vastly larger than had been generally believed.
Hubble’s observations were made possible by the pioneering innovations of Henrietta Swan Leavitt. She was the first person to demonstrate a “standard candle” — an astronomical object with a known intrinsic brightness. That discovery finally let astronomers calculate how far extremely distant objects are from Earth.
I love the term “standard candle”. Once you wrap your head around its significance, there are so many other ways that this idea could be applied.
With the right standard candle, we can illuminate the Universe.