in the end, was simply human. He didn't view his ignoring the early doubts about van Maanen's work as a scientific lapse but rather a personal one. “I faithfully went along with my friend van Maanen and he was wrong on the…motions of galaxies… [People] wonder why Shapley made this blunder. The reason he made it was that van Maanen was his friend and he believed in friends!” declared Shapley (oddly in the third person). He was also a man who was far too confident for his own good, if a popular tale often recounted at Mount Wilson is true. Around 1920 Shapley allegedly asked staffer Milton Humason to examine with the Blink some photographic plates of the Andromeda nebula Shapley had taken over the preceding three years. After comparing the plates for several weeks, Humason came to notice what appeared to be some variable stars in the nebula, possibly the same Cepheids that Hubble found a few years later. Humason, still in training, used a pen to mark off the suspects on the glass plates and went back to Shapley to show him the results. Shapley, not impressed, patiently explained to Humason why his spots couldn't possibly be Cepheids. Shapley was so certain of his position that he proceeded to take a handkerchief out of his pocket and rub out the marks, wiping the plates clean—not to mention wiping out his chances for further astronomical glory. While Shapley was waiting in 1920 to hear from Harvard about the directorship, he confided to one of his former Missouri professors, Oliver D. Kellogg, that he was frustrated by the university's indecision, since it disturbed his ability to prepare his research program for the next few years. Belying what he later said about there being “strict divisions” at Mount Wilson, Shapley noted that “spiral nebulae” were on his agenda and that “cosmogony” would be his future field. Had Shapley not gone to Harvard and instead stayed at Mount Wilson, he would surely have continued to look for novae in Andromeda, the purpose of his photographic survey, and perhaps come to recognize the Cepheids after all. He might have scooped Hubble. That he didn't only added to the ongoing rivalry between the two Missouri men.
Even decades later, when writing his memoir in the late 1960s, Shapley couldn't let go of the beefs with his rival. “The work that Hubble did on galaxies was very largely using my methods,” he recalled sulkingly. “He never acknowledged my priority, but there are people like that.” But then he grudgingly conceded that Hubble had “made himself very famous, and properly so. He was an excellent observer, better than I.” Hubble was patient.
It was that patience that enabled Hubble to methodically carry out the measurements that eluded earlier astronomers. Others had approached the nebular mystery yet gathered only tantalizing and incomplete hints; Hubble performed the painstaking tasks that closed the deal. That meant searching for stars and novae at the very limit of his telescope's resolving power and using them to measure a distance. Curtis had removed himself from big telescope access; Shapley refused to consider that spirals could be huge stellar systems. Only Hubble pursued the question with dogged effort and even he had been looking for novae at first, not Cepheids in particular. Luck certainly played a small role, but as Louis Pasteur once put it, “In the fields of observation, chance favors only the prepared mind.”
Once the news was out, reporters couldn't get enough of the tall and broad-shouldered Major Hubble, as they often addressed him. He was turning into an accomplished popular communicator. “There is just not one universe,” Hubble told a local journalist about his discovery. “Countless whole worlds, each of them a mighty universe, are strewn all over the sky. Like the proverbial grains of sand on the beach are the universes, each of them peopled with billions of stars or solar systems. Science has already taken a census of nearly ten million galactic systems or individual universes of stars.”
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