Baade, Shapley, and the Doubling of the Universe

In his recent review of Donald E. Osterbrock's book on Walter Baade (Physics Today, November 2002, page 69), Norriss S. Hetherington mentions "Harlow Shapley's shameless attempt to claim credit for the doubling of the scale of the universe."

Perhaps a more nuanced interpretation of Shapley's contribution to the cosmic distance scale problem is in order. The paper at issue is titled "Magellanic Clouds, VI. Revised Distances and Luminosities,"¹ and in it, Shapley redetermined the luminosities of globular-like clusters in the Magellanic Clouds. Assuming that such clusters are as luminous as galactic globular clusters, he found that the clouds are about twice as far away as had previously been believed. Shapley also pointed out in that paper that the noted increase in the distance of the clouds explains the "failure of the persistent Harvard searches for cluster-type cepheids in the Magellanic Clouds and their globular clusters." Shapley specifically cited Baade's similar failure to detect RR Lyrae variables at their expected luminosity level in the Andromeda galaxy; Baade's results were reported at the International Astronomical Union's meeting in Rome the previous year, 1952. Shapley cited Baade's previous work three times in his paper.

In a report on the astronomical highlights of 1952, Shapley placed Baade's contribution first when he wrote about the "general acceptance of the growing evidence, produced chiefly at Mount Wilson-Palomar [that is, by Baade] and at Harvard [by Shapley], . . . that the distances of the Magellanic Clouds, the Andromeda nebula, and nearly all external galaxies must be appreciably increased."² In retrospect, it seems likely that an overly enthusiastic New York Times article (4 January 1953, p. E8), based on Shapley's report to the American Astronomical Society, may lie at the root of the apparent controversy over who deserves credit for the 1952 doubling of the distance scale in the universe.

1. 1. H. Shapley, Proc. Natl. Acad. Sci. USA 39, 349 (1953).
2. 2. H. Shapley, Sky & Telescope, December 1952, p. 45.

Hetherington replies: "Shameless" is my characterization (and Walter Baade's) of Harlow Shapley's alleged attempt to take credit for doubling the scale of the universe, as described in Donald Osterbrock's biography of Baade. As Sidney van den Bergh noted, although a New York Times article quoted Shapley but did not even mention Baade, Shapley's articles in scientific journals acknowledged Baade's contribution.

One of many strengths of Osterbrock's historical work is his ability to probe behind the published record. He traced the New York Times article to a press release written by Sky & Telescope editor Charles Federer Jr, whose offices were at the Harvard College Observatory. According to Osterbrock, Federer got the story from Shapley, who based it on his oral presentation at the American Astronomical Society (AAS) meeting a few days earlier. Furthermore, Osterbrock cited exchanges of letters between astronomers, including staff members at Harvard, that deplored Shapley's perceived attempt to steal Baade's idea, work, and results.

Osterbrock also found correspondence to and from Otto Struve, then president of the International Astronomical Union, discussing whether Shapley should be censured by the IAU and the AAS. Another letter Osterbrock found was from Ira Bowen, director of the Mount Wilson and Palomar observatories, asking Donald Menzel, acting director at Harvard, to make sure that no more popular articles or news releases were issued crediting Baade's discovery to Shapley. Readers of Osterbrock's fascinating history can study the extensive and carefully documented factual material and judge for themselves Shapley's behavior in this matter.