The Shadows Know How Shadows Helped Give Birth to Astronomy |
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| Author:
| Orndorff, Beverly |
| Illustrator:
| Orndorff, Beverly |
| Cover Design by:
| Orndorff, Beverly |
| Drawings by:
| Orndorff, Beverly |
| Original Author:
| Orndorff, Beverly |
| Text by:
| Orndorff, Beverly |
| ISBN: | 978-0-9889886-4-4 |
| Publication Date: | Nov 2021 |
| Publisher: | Orndorff
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| Book Format: | Paperback |
| List Price: | USD $15.00 |
Book Description:
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A lot of the astronomical knowledge of ancient times came from observations of shadows, especially the shadows cast by gnomons that reflected the apparent motions of the sun. From such observations, early astronomers learned that the annual path of the sun was tilted with respect to the Earth's equator and to what degree. They could mark the moments of seasonal changes; they could gauge the passage of daylight, and they could determine the length of the year as measured by the sun's...
More DescriptionA lot of the astronomical knowledge of ancient times came from observations of shadows, especially the shadows cast by gnomons that reflected the apparent motions of the sun. From such observations, early astronomers learned that the annual path of the sun was tilted with respect to the Earth's equator and to what degree. They could mark the moments of seasonal changes; they could gauge the passage of daylight, and they could determine the length of the year as measured by the sun's annual cycle. Shadows enabled them to learn the size of the Earth, and the shadows of moon phases and eclipses gave them some initial ideas about the distances and sizes of the moon and sun. Ptolemy's Almagest, the standard astronomical text for 14 centuries, summarized those shadow-based techniques and the knowledge derived from them. Modern astronomy arose from critical analyses of Ptolemy's text starting with Copernicus, and extended by Kepler, Galileo, and Newton. So, in a sense, modern astronomy owes a lot to the studies of shadows by ancient astronomers.