How Marius Was Right and Galileo Was Wrong Even Though Galileo Was Right and Marius Was Wrong

Astronomers in the early 17th century misunderstood the images of stars that they saw in their telescopes. For this reason, the data a skilled observer of that time acquired via telescopic observation of the heavens appeared to support a geocentric Tychonic (or semi-Tychonic) world system, and not a heliocentric Copernican world system. Galileo Galilei made steps in the direction of letting observations lead him towards a Tychonic or semi-Tychonic world system. However, he ultimately backed the Copernican system, against the data he had on hand. By contrast, the German astronomer Simon Marius understood that data acquired by telescopic observation supported a Tychonic world system.Comment: Or, how telescopic observations in the early 17th century supported the Tychonic geocentric theory and how Simon Marius realized thi

17th Century Photometric Data in the Form of Johannes Hevelius's Telescopic Measurements of the Apparent Diameters of Stars

Johannes Hevelius's 1662 Mercurius in Sole Visus Gedani contains a table of magnitudes and apparent telescopic diameters of nineteen stars. The data conform to a simple model, suggesting that Hevelius produced what is essentially a table of surprisingly precise photometric data.Comment: To Appear in Baltic Astronomy Revision includes two additional references (Buchwald; Shara, Moffat, Webbink

Beyond Galileo: A translation of Giovanni Battista Riccioli's experiments regarding falling bodies and "air drag", as reported in his 1651 Almagestum Novum

The Italian astronomer Giovanni Battista Riccioli is commonly credited with performing the first precise experiments to determine the acceleration of a freely falling body, but he also went further, experimentally investigating what today would be called the effect of "air drag" on falling bodies. This paper consists of a translation of those experiments, with a brief analysis and commentary. Riccioli arrived at conclusions consistent with modern understanding of "air drag"

Doubting, Testing, and Confirming Galileo: A translation of Giovanni Battista Riccioli's experiments regarding the motion of a falling body, as reported in his 1651 Almagestum Novum

The Italian astronomer Giovanni Battista Riccioli is commonly credited with performing the first precise experiments to determine the acceleration of a freely falling body. Riccioli has been discussed by historians of science, sometimes positively but often not, but translations of his work into modern languages are not readily available. Presented here is a translation of his experiments regarding the nature of the motion of a falling body. Riccioli provides a thorough description of his experiments, and his data are quite good. He appears to have a model approach to science: He attacks the question of free fall with the expectation of disproving Galileo's ideas, yet he is convinced by his data that Galileo is indeed correct, and he promptly informs a former prot\'eg\'ee of Galileo's of the results

Riccioli Measures the Stars: Observations of the telescopic disks of stars as evidence against Copernicus and Galileo in the middle of the 17th century

G. B. Riccioli's 1651 Almagestum Novum contains a table of diameters of stars measured by Riccioli and his associates with a telescope. These telescopically measured star diameters are spurious, caused by the diffraction of light waves through the circular aperture of the telescope, but astronomers of the time, including Riccioli and Galileo Galilei, were unaware of this phenomenon. They believed that they were seeing the physical bodies of stars. In the Almagestum Novum Riccioli uses these telescopically measured disks to determine the physical sizes of stars under both geocentric (or geo-heliocentric - Tychonic) and heliocentric (Copernican) hypotheses. The physical sizes obtained under the Copernican hypothesis are immense - dwarfing the Earth, the Sun, and the Earth's orbit; even exceeding the distances to the stars given by Tycho Brahe. Thus Riccioli felt that telescopic observations were an effective argument against the Copernican system.Comment: Revised version includes extended Table 4; better Airy pattern image for Figure 1; wording changes to improve clarity of the paper, especially so as to distinguish more clearly between star sizes seen through the telescope and calculated physical sizes of stars

The Inquisition's Semicolon: Punctuation, Translation, and Science in the 1616 Condemnation of the Copernican System

This paper presents high-resolution images of the original document of the 24 February 1616 condemnation of the Copernican system, as being "foolish and absurd in philosophy", by a team of consultants for the Roman Inquisition. Secondary sources have disagreed as to the punctuation of the document. The paper includes a brief analysis of the punctuation and the possible effects of that punctuation on meaning. The original document and its punctuation may also have relevance to public perception of science and to science education.Comment: 22 pages, 1 table, 3 figures (2 very high resolution). Revised version (v2) includes minor changes based on feedback to v1. These include correction of several typos, two small adjustments to translation, et

Giovanni Battista Riccioli's Seventy-Seven Arguments Against the Motion of the Earth: An English Rendition of Almagestum Novum Part II, Book 9, Section 4, Chapter 34, Pages 472-7

In 1651 the Italian Jesuit Giovanni Battista Riccioli (1598-1671) published in his encyclopedic work on astronomy, the Almagestum Novum, 77 arguments against the Copernican movement of the Earth. These arguments are often mentioned in secondary sources, but a complete listing has not been readily available - thus one is provided here, in English. The 77 include interesting arguments from physics and astronomy that went on to become subjects of further investigation after the advent of Newtonian physics.Comment: 33 pages (mostly a long table of arguments) and 3 figure

Of Mites and Men: Johannes Kepler on Stars and Size

In his 1606 De Stella Nova, Johannes Kepler attempted to answer Tycho Brahe's argument that the Copernican heliocentric hypothesis required all the fixed stars to dwarf the Sun, something Brahe found to be a great drawback of that hypothesis. This paper includes a translation into English of Chapter 16 of De Stella Nova, in which Kepler discusses this argument, along with brief outlines of both Tycho's argument and Kepler's answer (which references snakes, mites, men, and divine power, among other things).Comment: Includes an English translation of Chapter 16 of Johannes Kepler's 1606 De Stella Nova. 19 pages, 4 figure

Letter to the Editor of Sky and Telescope Concerning Galileo's Observations of Mizar

Work published in Sky and Telescope in 2004 discusses Galileo's observations of the star Mizar. These observations raise questions regarding Galileo's assumptions about the universe and the conclusions he drew from his observations. Galileo would have expected Mizar to reveal annual parallax and thus provide evidence of Earth's motion, but Mizar shows no such parallax.Comment: Text of letter with footnotes to distinguish author's material from material editorially added (and later corrected) by Sky and Telescop

Regarding how Tycho Brahe noted the absurdity of the Copernican Theory regarding the Bigness of Stars, while the Copernicans appealed to God to answer that absurdity

Tycho Brahe, the most prominent and accomplished astronomer of his era, made measurements of the apparent sizes of the Sun, Moon, stars, and planets. From these he showed that within a geocentric cosmos these bodies were of comparable sizes, with the Sun being the largest body and the Moon the smallest. He further showed that within a heliocentric cosmos, the stars had to be absurdly large - with the smallest star dwarfing even the Sun. (The results of Tycho's calculations are illustrated in this paper.) Various Copernicans responded to this issue of observation and geometry by appealing to the power of God: They argued that giant stars were not absurd because even such giant objects were nothing compared to an infinite God, and that in fact the Copernican stars pointed out the power of God to humankind. Tycho rejected this argument.Comment: 20 pages, 4 figures, 2 tables + figures. v2 includes improved Gingerich reference on Tycho, minor correction