"VAR!" 100 Years Ago Tonight, Edwin Hubble Found a Star That Revealed the Vastness of the Universe
upstart writes:
"VAR!" 100 years ago tonight, Edwin Hubble found a star that revealed the vastness of the Universe:
How big is the Universe? Humanity made it all the way into the 1920s having no idea. Many people at that time thought that the Milky Way was the entire Universe. Yes, big, but not crazy big. Others thought that maybe those spirals and smudges we could see were in fact other galaxies altogether, which would mean the Universe is unfathomably large.
On the night of October 5-6, 1923 - 100 years ago tonight - Edwin Hubble made an observation that would settle the question once and for all. He took a 45-minute exposure of Andromeda, one of the largest and thus apparently nearest "spiral nebulae", and within it he spotted a single compelling star that we now call Hubble V1. We here on Earth will forever have a very special relationship with that star, because Hubble used its characteristics to show conclusively that Andromeda was not a "spiral nebula" within the Milky Way at all, but rather an entirely separate galaxy which he later estimated to be about 1 million (now understood to be closer to 2.5 million) light-years away.
In Hubble's time, many other "spiral nebulae" were known that appeared much smaller than Andromeda and were therefore presumably quite a bit farther away. Because of his observation a hundred years ago tonight, Hubble realized that even Andromeda, close enough to be seen with the naked eye, is on the order of 10 quintillion (10,000,000,000,000,000,000) miles away from Earth. And that must mean that the Universe is absurdly, almost comically, huge.
Imagine what Edwin Hubble felt like sitting there at Mt. Wilson Observatory, probably by himself late one evening, when he became the first person ever to know that for sure. His use of red ink and an exclamation point in the main figure of this diary illustrates that he knew darn well the significance of what he had found the minute he realized what it was.
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