He was one of the first to suggest the habitable or goldilocks zone for planets which he called the “liquid water belt.” But what he is most known for is correctly estimating the size of the Milky Way and the sun’s place within it.
This great accomplishment came when Shapley was working to determine distances to globular clusters under a fellowship at Princeton.
The discovery came when he was working late one night. He was so excited that he knew he had to share it with someone, so he found the only other person in the building: a cleaning lady.
The two stood looking at his graph as he explained that they were the only two people on Earth who understood that humanity lives, not near the center of a small star system, but in the suburbs of a vast wheel of stars.
