The Day We Found the Universe - Marcia Bartusiak [72]
Not everyone was convinced of this new cosmic scheme. Critics pointed to several weak points in Shapley's arguments, including Hale, who wondered whether the spirals were something other than Shapley imagined. But the Mount Wilson director still supported Shapley's bravado: “You have struck a trail of great promise…. I think you are right in making daring hypotheses, and in pushing the work ahead as you have done, as long as you…are prepared to substitute new hypotheses for old ones as rapidly as the evidence may demand,” Hale responded to Shapley from his wartime post in Washington. Hale preferred his astronomers to take chances. He didn't want them turning solely into unimaginative data gatherers, as Pickering, at Harvard, was wont to do.
But since Shapley had based his results using such novel methods as the Cepheid beacons and rashly ignored many uncertainties, acceptance was hardly unanimous. Other astronomers had been slowly and methodically measuring the galaxy's dimensions over many years by essentially counting stars, tracing out their distributions and movements over the sky and deep into space. The leader in this endeavor was the highly respected astronomer Jacobus C. Kapteyn, at the University of Groningen in the Netherlands. Though not possessing a good telescope, he organized a massive effort to measure the positions of hundreds of thousands of stars on plates taken at other observatories, partially with the help of state prisoners placed at his disposal. He reached the pinnacle of his life's work when he introduced what became known as the “Kapteyn Universe.” In this model, the largest portion of stars in our galaxy (there was a smaller fraction farther out) were gathered in a space roughly 30,000 light-years wide and 4,000 light-years thick, a sort of squashed football. Moreover, the Sun retained its plum position near the center. But Shapley was declaring that the Milky Way was ten times larger and the Sun pushed far off to the sidelines. It was extremely difficult for Kapteyn and his colleagues to imagine that their time-honored methods for tracking stellar distributions could be so flawed. Others thought so, too. Shapley had constructed a formidable distance ladder outward, but its calibration rested on a measly eleven Cepheids, whose motions were still highly uncertain. If those were wrong, the entire construct toward his fundamental verdict—what he called his “Big Galaxy”—would fall apart like a celestial house of cards. Kapteyn told Shapley that he was “building from above, while we are up from below… When will the time come that we thoroughly mesh?”
Conservative astronomers were most disturbed by the many analytical leaps of faith made by Shapley, who tended to speak, it was said, with a “carnival barker's certainty of truth.” Though brilliant and original, he was often quick to jump to conclusions based on meager observations. Accuracy seemed to be less important to him than developing a broad, grand picture. Walter Adams, for one, was sure that the fast and slow variable stars that Shapley lumped together in his computations were actually “two different breeds of cats.” (He was right; they were later found to be RR Lyrae stars, variables that are less massive and fainter than Cepheids.) And then there was the issue of Shapley's borrowing ideas and techniques from other astronomers without proper acknowledgment. Adams complained to Hale that Shapley “has never given the credit where it belongs.” In one paper published in the Proceedings of the National Academy, Shapley made no mention of either Hertzsprung or Leavitt, who had both certainly paved the way. This infuriated Adams. As one Harvard astronomer later put it, “I have never seen a quicker mind, a more agile sense of humor, or a more complete absence of what usually passes for humility.”
Shapley's critics were right to be cautious. In hindsight, he did get certain things