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Christopher M. Graney

Publications and source records attributed to Christopher M. Graney.

36 records · Page 2Linked to original sources
arXiv2011

126 Arguments Concerning the Motion of the Earth, as presented by Giovanni Battista Riccioli in his 1651 Almagestum Novum

In 1651 the Italian astronomer Giovanni Battista Riccioli published within his Almagestum Novum, a massive 1500 page treatise on astronomy, a discussion of 126 arguments for and against the Copernican hypothesis (49 for, 77 against). A synopsis of each argument is presented here, with discussion and analysis. Seen through Riccioli's 126 arguments, the debate over the Copernican hypothesis appears dynamic and indeed similar to more modern scientific debates. Both sides present good arguments as point and counter-point. Religious arguments play a minor role in the debate; careful, reproducible experiments a major role. To Riccioli, the anti-Copernican arguments carry the greater weight, on the basis of a few key arguments against which the Copernicans have no good response. These include arguments based on telescopic observations of stars, and on the apparent absence of what today would be called "Coriolis Effect" phenomena; both have been overlooked by the historical record (which paints a picture of the 126 arguments that little resembles them). Given the available scientific knowledge in 1651, a geo-heliocentric hypothesis clearly had real strength, but Riccioli presents it as merely the "least absurd" available model - perhaps comparable to the Standard Model in particle physics today - and not as a fully coherent theory. Riccioli's work sheds light on a fascinating piece of the history of astronomy, and highlights the competence of scientists of his time.

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arXiv2010

The Coriolis Effect Apparently Described in Giovanni Battista Riccioli's Arguments Against the Motion of the Earth: An English Rendition of Almagestum Novum Part II, Book 9, Section 4, Chapter 21, Pages 425, 426-7

In his encyclopedic work on astronomy, the 1651 Almagestum Novum, the Italian Jesuit Giovanni Battista Riccioli (1598-1671) argued against the movement of the Earth on the grounds that (among other things), if the Earth rotated, that rotation should produce a deflection in the trajectories of projectiles. This argument appears to be an early description of the Coriolis effect.

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arXiv2010

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.

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arXiv2010

Further Argument Against the Motion of the Earth, Based on Telescopic Observations of the Stars: An English Rendition of Chapter 30, Book 9, Section 4, Pages 460-463 of the Almagestum Novum Volume II of G. B. Riccioli

The Italian Jesuit astronomer Giovanni Battista (Giambattista) Riccioli constructed a powerful, thoroughly scientific argument in favor of geocentrism - an argument based on telescopic observations of stars. This paper contains a rendition of a chapter from Riccioli's Almagestum Novum in which he lays out this argument. Riccioli opposed Galileo's heliocentrism, but like Galileo, relied on telescopic observations to make his case. Riccioli's observations and argument were both valid, lacking only in that the functioning of the telescope was not fully understood at the time.

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arXiv2010

On the telescopic disks of stars - a review and analysis of stellar observations from the early 17th through the middle 19th centuries

Since the dawn of telescopic astronomy astronomers have observed and measured the "spurious" telescopic disks of stars, generally reporting that brighter stars have larger disks than fainter stars. Early observers such as Galileo Galilei interpreted these disks as being the physical bodies of stars; later observers such as William Herschel understood them to be spurious; some, such as Christian Huygens, argued that stars show no disks at all. In the early 19th century George B. Airy produced a theoretical explanation of star images sufficient to explain all historical observations, but astronomers were slow to fully recognize this. Even today conventional wisdom concerning stars and telescopes stands at odds to both historical observations and Airy's theory. We give a detailed analysis of both historical observations and Airy's theory, illustrating how Airy's theory explains the historical observations, from Galileo to Huygens to Herschel. We argue that the observations themselves appear in all cases to be valid and worth further study.

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arXiv2010

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.

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arXiv2009

Regarding the Potential Impact of Double Star Observations on Conceptions of the Universe of Stars in the Early 17th Century

Galileo Galilei believed that stars were distant suns whose sizes, measured via his telescope, were a direct indication of distance -- fainter stars (appearing smaller in the telescope) were farther away than brighter ones. Galileo argued in his Dialogue that telescopic observation of a chance alignment of a faint (distant) and bright (closer) star would reveal annual parallax, if such double stars could be found. This would provide support both for Galileo's ideas concerning the nature of stars and for the motion of the Earth. However, Galileo actually made observations of such double stars, well before publication of the Dialogue. We show that the results of these observations, and the likely results of observations of any double star that was a viable subject for Galileo's telescope, would undermine Galileo's ideas, not support them. We argue that such observations would lead either to the more correct conclusion that stars were sun-like bodies of varying sizes which could be physically grouped, or to the less correct conclusion that stars are not sun-like bodies, and even to the idea that the Earth did not move. Lastly, we contrast these conclusions to those reached through applying Galileo's ideas to observations of visible stars as a whole.

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arXiv2009

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.

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arXiv2009

Visible Stars as Apparent Observational Evidence in Favor of the Copernican Principle in the Early 17th Century

The Copernican Principle (which says the Earth and sun are not unique) should have observational consequences and thus be testable. Galileo Galilei thought he could measure the true angular diameters of stars with his telescope; according to him, stars visible to the naked eye range in diameter from a fraction of a second to several seconds of arc. He used this and the Copernican Principle assumption that stars are suns as a method of determining stellar distances. The expected numbers of naked eye stars brighter than a given magnitude can be calculated via Galileo's methods; the results are consistent with data obtained from counting naked eye stars. Thus the total number of stars visible to the naked eye as a function of magnitude would appear to Galileo to be data supporting the Copernican Principle.

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arXiv2008

The Naked Eye Stars as Data Supporting Galileo's Copernican Views

The aggregate appearance of the naked-eye stars would appear to Galileo to be direct observational support for his ideas about the stars, and indirect observational support for the Copernican theory over the rival Tychonic theory. Brief historical background is also included.

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arXiv2008

Objects In Telescope Are Farther Than They Appear: How diffraction tricked Galileo into mismeasuring the distances to the stars

Galileo determined distances to stars based on the assumption that stars were suns, the apparent sizes of stars as seen through his telescope, and basic geometry. However, the apparent sizes that he measured were the result of diffraction and not related to the actual sizes of the stars. Galileo's methods and observations were good, but since he was unknowingly observing diffraction artifacts and not the physical bodies of stars he greatly underestimated the distances to the stars.

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arXiv2008

On the Accuracy of Galileo's Observations

Galileo Galilei had sufficient skill as an observer and instrument builder to be able to measure the positions and apparent sizes of objects seen through his telescopes to an accuracy of 2" or better. However, Galileo had no knowledge of wave optics, so when he was measuring stellar apparent sizes he was producing very accurate measurements of diffraction artifacts and not physical bodies.

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arXiv2007

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.

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arXiv2006

Galileo's Double Star: The Experiment That "Proved" the Earth Did Not Move

Great opportunities arise for teaching physics, astronomy, and their histories when new discoveries are made that involve concepts accessible to students at every level. Such an opportunity currently exists thanks to the fact that notes written by Galileo indicating that he observed the double star Mizar in the "Big Dipper" have recently come to light. His measurements of this star, given the scientific knowledge at the time, strongly supported the theory that the Earth was fixed in space and not moving. Had Galileo published these results, it is likely that widespread acceptance of the heliocentric theory in scientific circles would have been significantly delayed. In light of these notes, his later reference in his Dialogue to using double stars as a means of proving that the Earth was in motion is puzzling. The physics and mathematics behind Galileo's work is easily within reach of students in introductory physics and astronomy courses, so discussion of Galileo's Mizar work and its interesting implications can be used in virtually any class.

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arXiv2006

The Accuracy of Galileo's Observations and the Early Search for Stellar Parallax

The question of annual stellar parallax is usually viewed as having been a "win-win situation" for seventeenth-century astronomers who subscribed to the Copernican view of universe in which the Earth orbits the Sun and the Sun is one of many suns (the fixed stars) scattered throughout space. Detecting parallax would be solid evidence for the Earth's motion, but failure to detect parallax could be explained by the stars lying at great distances. Recent work pertaining to Galileo's observations of double stars illustrates Galileo's skill as an observer. It also indicates that, given the knowledge of optics of the time, Galileo could expect his measurements to be accurate enough that they would have revealed stellar parallax had it existed. Thus parallax was not a "win-win situation" after all. It could be solid evidence against the Earth's motion, evidence which fortunately did not dissuade Galileo from the Copernican view.

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