The Moon that Wasn't

This book details the history of one of astronomy's many spurious objects, the satellite of Venus. Meticulously documented and based on a large collection of primary sources, the book addresses the history of planetary astronomy in a novel way.

The planet Venus is the closest neighbour to the Earth and in several respects similar to our globe. It revolves around the Sun at an average distance of 0. 72 astronomical units, in an elliptical orbit of eccentricity 0. 007. The corresponding 3 numbers for the Earth are 1 and 0. 017. The mean density of Venus is 5. 2 g/cm , 3 that of the Earth 5. 5 g/cm . Venus' acceleration of gravity at its equator is 8. 9 2 2 m/s , compared with 9. 8 m/s at the Earth. The escape velocity is 10. 4 km/s, while the corresponding ?gure of the Earth is 11. 2 km/s. Although the mass of Venus is somewhat smaller than that of the Earth the ratio is M /M =0. 815 V E the diameters of the two planets are almost the same. In other words, Venus is indeed a sister planet of the Earth. In earlier times, when almost nothing was known about the physical con- tions of Venus, the similarity appeared even stronger than today. Not only was Venus' period of rotation thought to be close to that of the Earth, it wasalso p- sible (and indeed common) to imagine intelligent life on Venus.

First book ever that recounts the story of Venus' moon and provides it the place in the history of astronomy that it deserves Meticulously documented and based on a large collection of primary sources By relating the case of Venus' moon to the cultural climate in the era of enlightenment, it makes a connection between history of astronomy and history of culture

Autorentext
After graduation from the University of Copenhagen in Physics and Chemistry, and a period as teacher in gymnasium schools, Helge Kragh became Associate Professor at Cornell University, Departments of History and Physics. Later, he took positions as Curator at the Steno Museum for Science and Medicine and Professor of the History of Science at the University of Oslo, Norway. Since 1997, he has been Professor of the History of Science and Technology, University of Aarhus, Denmark. He is a Member of the Royal Danish Academy of Science, the International Academy for the History of Science, and of the European Academy of Science. He was President of the European Society for the History of Science (2008-10).

Klappentext

This book details the history of one of astronomy's many spurious objects, the satellite of Venus. First spotted in 1645, the non-existing moon was observed more than a dozen times until the late eighteenth century. Although few astronomers believed in the existence of the moon after about 1770, it continued to attract attention for at least another century. However, it has largely disappeared from the history of astronomy, and the rich historical sources have never been exploited. By telling the story of the enigmatic satellite in its proper historical context it is demonstrated that it was much more than a mere curiosity in the annals of astronomy Frederick II of Prussia was familiar with it, and so was Bonnet, Kant and Voltaire. The satellite of Venus belongs to the same category as other fictitious celestial bodies (such as the planet Vulcan), yet it had its own life and fascinating historical trajectory. By following this trajectory, the history of planetary astronomy is addressed in a novel way.

Inhalt
A moon or not? A century of confusion.- From climax to anticlimax.- Contemporary analysis and criticism.- A spurious but persistent satellite.- Closure: the discussion of the 1880s.- Conclusion, and a note on the satellites of Uranus.