Steven J. Dick’s Discovery and Classification in Astronomy

Thomas Jefferson did not say that it “was easier to believe that two Yankee professors could lie than to admit that stones could fall from heaven.” But he could have because the celestial origin of meteors and meteorites was not established until 1863. Steven J. Dick (NASA Chief Historian, 2003-2009) calls earlier claims the “pre-discovery” phase. After discovery—the correct identification of an object—come classification, controversy, and consensus. 

Pre-discovery of the Sun, Moon, and stars begins with our hominid ancestors. Uranus and Neptune had pre-discovery phases because they were spotted and recorded as stars before they were identified as planets. Uranus was recorded (as a star) by British Astronomer Royal John Flamsteed six times in 1690. Galileo recorded Neptune (as a star) on December 28, 1612, and January 27, 1613. When William Herschel identified it as a planet, there was some controversy between 1781 and 1783 but the matter was soon settled. Pluto, on the other hand, stands as a counter-example. It had no pre-discovery phase. When discovered, it was accepted as a planet. Only later did controversy change its classification and a new consensus evolve. The catalyst for that change was understanding, and the process was an evolution.

The stars were even less tractable and nebulae all the more difficult to isolate into classes. At first astronomers expected that better telescopes would resolve all nebulae into fields of stars. That did happen with some. Others were found to be huge volumes of gas or dust that absorb or reflect or emit radiation. Still others eventually were identified as types of galaxies, again, with some controversies that are not yet entirely settled.

Discovery and Classification in Astronomy: Controversy and Consensus by Steven J. Dick (Cambridge University Press, 2013), is a taxonomic history. Dick alludes to parallels in the development of biology and chemistry which he offers as more mature paradigms. The periodic table of elements allowed predictions. Astronomy has nothing like it. Biology still has controversies but it has millions of species to consider. Astronomy has fewer than 100, 82 by his count. In most cases, each discovery was a thing-in-itself until improved understanding (usually through controversy) revealed others of its kind. 

The main narrative of 340 pages delivers a chronology by types from planets to quasars and then reviews the works and publications to reveal the patterns (Part IV) and the drivers of discovery (Part V). Part VI closes with The Meaning of Discovery.

“… discoveries end with a basic understanding of the fundamental properties of a class, but before mature understanding, as defined by knowing an object's place in an evolutionary scheme.” (page 331). The process can take centuries as with the planetary nebulae. Dick also believes that since 1960 or so we have come to a mature evolutionary scheme for the universe. (page 331). 

Having presented the facts, Dick then organizes them into a Three Kingdoms model: Planets, Stars, and Galaxies. It fits on two landscape pages as Appendix 1. Appendix 2 “Astronomical Discoveries and Their Extended Structure” is a detailed tabulation of 82 objects, from Novae through  Proto-Galactic Clouds, identifying the discoverer and citing the pre-discoveries. 

I got the book from the library because in our home we are of one mind on not acquiring more stuff. However, I bought it because it is more conceptual than a history of astronomy or, more narrowly, astrophysics (which I regard as the touchstone of astronomy) and it is more concrete than a philosophy of science. 

As valuable as I regard the work, I do differ from Dick on his metaphysics and epistemology, and I have some quibbles with his history. In the main, however, his assertions are supported by deep foundations of facts in their correct contexts. 

One oversight is in the history of meteorites. Dick makes no mention of the surviving commentaries by Plutarch, Pliny, and Diogenes Laertius about Anaxagoras of Klazomenai who allegedly tracked and found a meteorite and from that posited that the stars are hot rocks and that the Sun is such a hot rock, “larger than the Peloponnesus.” That being so, I still agree with Steven Weinberg and Alan Hirshfeld that as much as we can relate to the early savants, their hypotheses were not science. 

Dick also credits Edmund Husserl and phenomenology, requiring that understanding be identified with “the thing itself” in other words to understand and appreciate an object without regard to arbitrary—and perhaps false—contexts. For that, however, I look to Immanuel Kant’s “das Ding an sich.” 

“The thing itself” was a primary consideration for William W. Morgan who extended the Harvard classification system (O B A F G K M) by parameterizing luminosity classes for super giants, bright giants, normal giants, subgiants, and main sequence stars: V, IV, III, II, I. Underlying the system Morgan considered the ratios of stellar spectra, not just the lines themselves. William W. Morgan published the Atlas of Stellar Spectra, with an Outline of Spectral Classification with Philip C. Keenan and Edith Kellman in 1943. Dick explicitly examines the fact that Morgan cited Husserl, and then abandoned any phenomenological framework for that research.

As for Thomas Jefferson, the historians at Monticello have come to his rescue. See “Thomas Jefferson and the Meteorites,” posted November 14, 2008, as “Who is the liar now?” by 

Anna Berkes, at https://www.monticello.org/site/blog-and-community/posts/who-liar-now.  

From there you can find a lengthy review of A professor, a president, and a meteor, by Cathryn J. Prince. (Amherst, New York: Prometheus Books, 2011), at Meteoritics & Planetary Science 46, Nr 10, 1608–1616 (2011) by Ursula B. Marvin of the Harvard-Smithsonian Center for Astrophysics.

"Between 1794 and 1804 an astonishing succession of new ideas, four witnessed falls of meteorites and chemical analyses of them, took place that established meteoritics as a new branch of science. Prince ignores this chain of events almost entirely. Her approach leaves such a gap in the founding of meteoritics that herewith is a brief sketch of the main events that are missing from her book.

"In April, 1794, Ernst F. F. Chladni of Wittenberg published the first modern book on meteorites and their origins. He began by discussing the Pallas Iron, a huge mass of metallic iron found on a high mountain in Siberia. After reasoning away hypotheses that it formed in the atmosphere, or was smelted from ore by lightning or by prehistoric men, he concluded that it, and other masses like it, must have fallen from cosmic space. This was a completely new concept at a time when space was ‘‘known’’ to be empty." The Meteoritical Society, 2011, at https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1945-5100.2011.01242.x

Thomas Jefferson only wrote in a letter: “It may be very difficult to explain how the stone you possess came into the position in which it was found. But is it easier to explain how it got into the clouds from whence it is supposed to have fallen?”  (Transcription from Lipscomb-Bergh 11:441-2 - the polygraph copy of this letter is online here.)

http://memory.loc.gov/master/mss/mtj/mtj1/040/1000/1084.jpg

The Thomas Jefferson Papers Series 1. General Correspondence. 1651-1827

Thomas Jefferson to Daniel Salmon, February 15, 1808

http://hdl.loc.gov/loc.mss/mtj.mtjbib018246 Image 1084 of 1330.

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